election. his opponents have constantly attacked him on the ailing economy. the president tried to turn the tables. >> they know they don't have a plan to create jobs. they don't have a plan to grow the economy. they don't have a plan to revive the middle class. what they're selling you are not buying. >> reporter: all four candidates were on the road monday. vice president joe biden campaigned in north carolina, attacking ryan's budget plan and calling his proposals irresponsible. john and paula? >> thank you. >> it's interesting, chris christie is going to have a prominent role. we know who the keynote speaker was in 2004, became the president, 2008. chris christie was a name out there for vice president. >> a strong one. >> pawlenty, former governor, two-time governor of minnesota. he was actually speaking on romney's behalf on sunday morning on a lot of the political shows. and then you had marco rubio introduce romney in florida. interesting how the guys were