very difficult for china because we are, believe it, we are holding china up. they're taking so much money. they're draining our country. and they're toying with us with north korea. so north korea is totally under the control, without china, they wouldn't eat. they wouldn't have food. they wouldn't have anything. so china should do it. >> all right. those words from donald trump. now a live look at marco rubio who's stumping in iowa. a few hours ago, he lashed out at the president and the former secretary of state, hillary clinton, in a series of tweets saying, quote, if this test is confirmed, it will just be the latest example of the failed obama/clinton foreign policy. our senior political reporter manu raju is tracking the story from marshalltown, iowa. good morning. >> reporter: good morning. rubio just talked about this right now. he discussed how kim jong-un is a lunatic and how north korea needs to be addressed aggressively. he thinks that this is an issue