(SOUNDBITE)(English) U.S. PRESIDENT DONALD TRUMP, SAYING: "Joe Biden was a disaster." For weeks they're exchanged jabs from afar.
(SOUNDBITE)(English) FORMER U.S. VICE PRESIDENT JOE BIDEN, SAYING: "This White House is literally a bully pulpit." But on Tuesday Trump and Biden will both be in Iowa making their case to would-be caucus goers.
In excerpts of his speech released to media, Biden says that Trump is quote an "existential threat to America" and that "we have to clearly and firmly reject his view of the presidency." The White House tuesday pushed back on the former vice president.
(SOUNDBITE)(English) WHITE HOUSE SPOKESWOMAN SARAH SANDERS, SAYING: "I think Joe Biden has a lot of questions he needs to answer himself.
The idea that he would say that the president poses any type of threat is truly laughable." In the state, Trump will tour a plant to tout his administration's recent approval of the expanded use of corn-based ethanol in gasoline, a move applauded by Iowa farmers and ethanol producers.
It's also a topic Biden faces lingering questions on… over his push in 2014 to slash the amount of ethanol refiners must blend into the country's fuel supply.
Still....a recent poll shows Biden still leads the Democratic pack of presidential contenders in Iowa.
The former VP is also expected to lay out his plan to address U.S. tensions with China, as Iowa farmers have been among the hardest hit by President Trump's trade war.