. . This is the cbs overnight news. Welcome to the overnight news, im elaine quijano. It is almost over the most contentious president ial election in recent memory comes to a head tomorrow. When Voters Decide whether Hillary Clinton or donald trump will be the 45th president of the United States. But in the 11th hour, fbi director james comey threw another wild card intohe comey sent a letter to congress saying the bureau concluded its review of the latest batch of Hillary Clintonrelated e drk mails and no charges will be brought against the former secretary of state. And nancy cordes is traveling with the clinton campaign. Clinton on her way from philadelphia to cleveland when news of comeys letter broke, Campaign Aide could be seen reading it allowed. Comey wrote after reviewing a large volume of emails we have not changed when he recommended against prosecuting clinton. Communications director, jennifer palmieri. We are glad to see, that he has found as we are confident that he would, he found the conclusions he really reached in july. And were glad this matter is resolved. Hillary clinton began her sunday like Many Americans at church. . Secretary you are going to stand . . Oh, yeah . She told the africanamerican congregation at Mount Airy Church that their civil rights are on the ballot. Everything you care about, everything i care about and i have worked for is at stake. Minority turnout is critical, she campaigned with a series of high profile black supporters. Power couple beyonce and jayz. Basketball superstar, lebron james, and, new jersey senator, cory booker. We have got to remember that work together, we win together. Reporter president obama was dispatched to florida today where black churches marked the final day of early voting with tradition known as souls to the polls. The clinton camp feels confident in nevada after a surge of voters in las vegas prompted officials to extend early voting for several hours. Michigan on the other hand has become so close that clinton its head back there on monday. And it was her husbands sole stop today. I believe hillary will carry michigan if we turn out. A clinton aide says her reaction to the comey letter was understated and she hasnt mentioned it here in cleveland. They believe the word will get out whether clinton talks about it or not in the closing days. Elaine. Nancy cordes, thank you. When he got the news about Hillary Clintons emails. Here is major garrett. You have to understand, its a rigged system. And she is protected. The before an enthusiastic minnesota crowd, donald trump alluded to fbi director james comeys decision not to charge Hillary Clinton in the latest round of her email scandal but said it did not put the controversy to rest. Hillary clinton will be under investigation for a long, long time. For her many crimes against our nation, our people, our democracy. Likely concluding in a criminal reporter earlier in iowa, thousands gathered for a noon rally in republican sioux city. We are doing great in iowa. We are doing great in ohio. I think we are going to win pennsylvania. That was trump in tampa saturday morning. Today, five more stops. But all has not been calm. A protester in rno last night. We have one of the guys from the Hillary Clinton campaign. Some one nearby shouted gun and the secret service whisked trump offstage. There was no gun. The protester was later released. Trump came back to finish. Nobody said it was going to be easy for us. Trumps closing argument. We are going to drain the swamp. Reporter a pledge to turn washington upside down. Real change begins with immediately repealing and replacing obamacare. Reporter the promised demise of obamacare is now nearly as popular as trumps long standing promise to build a wall on the southern border. Elaine the message ring with an oddly advantageous ring here in minnesota. Where the democratic governor, mark dayton is frequently quoted by trump saying, the Affordable Care act is no longer affordable. Major garrett. Thank you. Latest average of National Polls shows Hillary Clinton about 2 points ahead of donald trump. Tonight, our final Battleground Tracker poll before the election shows a dead heat in florida where the candidates each have 45 of the vote. In ohio, donald trump is one point ahead of Hillary Clinton. 46 to 45 . For more on this, we turn to cbs News Elections director anthony salvanto. One of the reasons behind the tightening races, donaldru has gotten some more of the previously unsure, the undecided voters, in both of the states. Now, there werent that many to begin with. But one of the things we have seen from these voters as with many voters overall is that they have been looking for change. What they tell us now is that they increasingly see Hillary Clinton as part of or connected to what they dont like about politics. Trump as entirely separate from it. That could be one reason theyre moving over. The other is that partisans, reliable republican voters, who have not been as fully with donald trump through the campaign as democrats have been with Hillary Clinton, well, some of those republicans have started to come back home. Started to say that they now will vote for donald trump. Thats behind some of his movement. But as we head into tuesday night, the key thing to watch is, both of these states are critical to Donald Trumps path. He need ohio. He need florida. Hillary clinto them. The map would still favor her in that regard. But, watch on tuesday if she can hang on to places like virginia. Like pennsylvania. If she can hold both of those, she doesnt need a lot more to still get the electoral votes she will need to get elected. Anthony salvanto. Thank you. Anthony and the rest of the campaign 2016 team will be here tuesday night with full coverage of election results. It all begins when the first polls close at 7 00 p. M. Eastern the cbs overnight news will be right back. Almost sixty million americans are affected by mental illness. Together we can help them with three simple words. My name is chris noth cer you taught him how to hit a baseball. How to hit a receiver. You even taught him how to hit the open man. But how much time have you spent teaching him. The world is closely watching the election. Manuel bojorquez gives us the view from mexico city. Manuel. Reporter there is great concern here a Trump Victory could cause an economic shock and mexicos central bank is exploring ways to mitigate that. One example, the peso, it goes down in value when trump goes up in the polls. Much of that has to do with his rallying cry against nafta, the Free Trade Agreement which include the u. S. mexico, trump says is killing u. S. Jobs and wants to do away with it. You are bringing in from the United States . I have spoken with mexican Business Owners who say he is ignoring the fact more than 1 million u. S. Jobs depend on trade with mexico. A mexican senator i spoke with said he is already drafting legislation that would seek to prevent a Trump Administration from making mexico pay for the one of trumps signature issues. Even before the election, it has led to a battle of word between trump and the mexican president. Who invited the republican nominee to visit back in august. But the deep dislike of trump here in mexico goes back to the very beginning of his campaign, when he labeled some mexican immigrants as criminals and rapists. That led to protests here including the beading of trump pinatas and unflattering political cartoons that are in the newspapers almost daily. All of that makes Hillary Clinton the heavily favored candidate south of the border if only by default. Elaine, the general feeling here is that donald trump has the made this election personal for the people of mexico. With much at stake for both countries. Manuel bojorquez, manuel, thank you. A man arrested by the white house saturday wearing a mask and carrying a gun. The man was confronted by secret custody after a brief struggle. The president was not home at the time. A South Carolina man accused of holding a woman chained inside a storage container for weeks was in court sunday. Investigators say 45yearold has confessed to killing four other people exactly 13 years ago this weekend. He is a suspect in at least three other deaths. A Police Officer was killed in west valley utah. 25yearold officer Cody Brotherson was hit buy a car during a chase. He was outside his police car. Three people are under arrest. The officer is survived by his parents, two brothers, and his fiance. Colonial gas pipeline that burst into flames in alabama last week, reopened today. It carries gasoline from the gulf coast to new york city. It will be a few days before deliveries are become to there mall. One person was killed and four piece of excavation equipment hit the pipeline apparently causing it to explode. At the vatican today, pope francis had a special mass for 1,000 prisoners from around the world. The pope said he wanted to bring a message of mercy and help to inmates and called for improved Living Conditions in prisons all over the word. A 20yearold runner from eritrea became the youngest man to win the new york city marathon. He crossed the finish line in 2 08. Among the women, a kenyan, won the Third Straight new york city marathon. More than 50,000 people ran this year. Coming up next, the challenges of covering campaign 2016 in the classroom. Hey julie, i know todays critical, but i really. Need a sick day. Dads dont take sick days. Dads take dayquil severe the. Nondrowsy, coughing, aching, fever, sore throat, stuffy. Many teachers have been treading carefully in the classroom when it comes to talking about this years election. Some changed lesson plans to avoid the language and subjects that have come up. Mireya villarreal introduces us to one teacher who says no topic is offlimits. In this history classroom, daniel jost blends pop culture. Did you know salt and pepper were talking immigration . And politics. I want to make them fall in love with the content of the study of history. And if you do those things, students are going to be very quick to want to learn and do Amazing Things in the classroom. Of this election has captured the kids attention but has been an opportunity to teach both the strengths and weaknesses of democracy. We are going to build the wall 100 . Well will not build a wall. I think you would do a disservice if you dont embrace it. Thee are teachable moments. There are concerns what this rhetoric means for their family. Will this turn into policy . And we, we constantly are engaging in these conversations, not shying away from them. Its because you have some people who do that does not justify for labelling a group of people. Reporter roughly 80 is high poverty from neighborhoods and most parents are immigrants. Trump doesnt know, he doesnt know. He doesnt support any with actual stats or actual researches. He just says it. Sure there are some, that commit crimes, there are also some white people who commit crimes, going by that logic you could say all white people are reporter in a report published by Southern Poverty Law Center more than 40 of teachers surveyed said they were hesitant to teach about the election. And more than half have seen an increase in uncivil discourse. There is no topic that is offlimits. None. His goal is for students to examine what the candidates are saying in the context of american history. How much of a gift has this been for your lesson plan over the last year . All most been a gift in that it is very relevant to stew students. But a curse. There are distractions. Cant help but talk about the things students are hearing about or seeing in the news. Still he says election day cant come soon enough. Mireya villarreal, cbs news, los angeles. Up next, hightech blimps patrolling the u. S. mexico along the u. S. mexico border an air war between drug cartels and federal agents. Chris martinez reports from the border in arizona. Reporter one of the most powerful tools to protect the border is suspended high above the arizona desert. Agents call it their eye in the sky. We fly as close to 24 365. The tethered t. A. R. S. Monitors the u. S. mexico border. Six blimps from arizona to texas, carry radar that can detect aircraft flying too low for conventional radar to see. That includes drones. And these home made low flying planes smugglers use to deliver drugs over the border. This is the control . The steering. Aircraft are equipped with drop baskets like this. So smugglers can dump payload midair to Cartel Members inside the u. S. Our Law Enforcement operators see that on the radar will engage and get the drugs, get the bad guys waiting for the drugs. Reporter the t. A. R. S. Radar images sent to this military base in california where detection officers watch for potential threats. I am going to zoom in. My focus is for what doesnt seem right in this area. Once something is spotted Border Patrol teams can be in at the air within three minutes. Mexicos northern most border. Smugglers often risk flying dangerously low to deliver their drugs. This is how close some will fly . Yes, hug the mountains to barack up profile. Reporter if the smuggler makes it over the border, the t. A. R. S. Technology helps track down the drugs before it gets into the wrong hand. Still ahead, well go swimming with drones. More doing chores for mom per roll bounty is more absorbent, bounty, the quicker picker upper ugh, its only lunchtime and my Cold Medicines wearing off. Im dragging. Yeah, that stuff only lasts a few hours. Or, take mucinex. One pill fights congestion for 12 hours. No thank you very much, shes gonna stick with the shortterm stuff. 12 hours . Guess i wont be seeing you for a while. Is that a bisque . I just lost my appetite. Why take medicines that only last 4 hours, lasts 12 hours . Start the relief. Ditch the misery. Lets end this. When it comes to drones, the sky is not the limit. Ben tracy shows us a new type of underwater drone that can turn any one into an ocean explorer. Reporter it cuts through the water like a fish. Underwater drone can also turn on a dime. Its called trident. And one of its creators, eric stagpole hopes it allows any one to become an explorer. What are you hoping to accomplish . My hope is we can get 10,000 eyes in water looking at parts of the world no one has ever seen before. In the past exploration has been something you see someone else do, always the famous explorers who do their expedition, come back and found. Reporter undersea exploration began in the 1940s. Here we go. Reporter in 2013, oscar winning director James Cameron designed and built a oneman sub, to explore the deepest part of the pacific, nearly seven miles down. Trident can only dive about the length of a football field. But thats deep enough to explore countless ship wrecks. They have been used to mexico, antarctica to explore under the ice, people took them to mt. Everest, explored a lake. Last summer he sent his drone into lake tahoe where they found the remains of a steamer ship the queen of the lake. We actually were able to land on a sink in the bathroom, built in the 100s on the shipwreck not seen for 70 years. That was just awesome. Reporter we joined stagpoles team on a test run of the new model in monterey bay on californias central coast. What are we going to look for out here . Right now we are over a place large white sea anomes found 60 feet down. Laura james noticed sick and dying sea stars near her home in seattle and began documenting the devastation. Scientists believe tied to climate change. When i look at the water i see not just the surface but the murky deep below. I want to know more about it. Legend Walter Cronkite and one giant leap for election woman what does it feel like when a woman is having a heart attack . Chest pain, like theres a ton of weight on your chest. Severe shortness of breath. Unexplained nausea. Cold sweats. Theres an unusual tiredness and fatigue. Theres unfamiliar dizziness or lightheadedness. Unusual pain in your back, neck, jaw, one or both arms, even your upper stomach, are signs youre having a heart attack. Dont make excuses. Make the call to 911 immediately. Learn more at womenshealth. Gov heartattack. You can help children in low income neighborhoods get the help they need to stay in school and go on to college. I have a dream foundation provides mentoring, academic help, and tuition to make this dream come true. Learn how this Program Helps students build life skills while increasing High School Graduation and College Participation rates. Visit this past friday would have been the 100th birthday of Walter Cronkite. To night we look back at one of the many highlight from his career, coverage of the 1952 president ial election broke new ground in broadcast journalism. As jamie yuckas shows us it wasnt always easy for tv pioneers. The First National broadcast of a president ial election. The 1952 race between Dwight Eisenhower and adele stevenson. General eisenhower leading at this moment. Reporter the first time the network use a computer to predict the outcome of an election. This is not a joke or trick. Newsman struggled to explain the univac, an enormous computer housed miles away in philadelphia. On the right of the univac typewriter. The way univac talks. Not always on cue. Can you say something, univac . Anything to say to the