Biden, Trump Assailing Each Other in Dueling Iowa Visits

President Donald Trump and Democrat Joe Biden are assailing each other in overlapping visits to the key state of Iowa on Tuesday, previewing what the country might get in next year's election if Biden becomes his party's nominee.

The president unleashed a series of schoolyard taunts of the former vice president before taking off from the White House, declaring "Joe Biden is a dummy."

"I'd rather run against Biden than anybody," he said. "I think he's the weakest mentally and I like running against people that are weak mentally."

Biden, too, was going on the offense, campaigning alone in Iowa in an effort to present himself as the front-runner in a field of two dozen Democrats. He released an advance text of his speech in which he slams Trump, essentially goading the president to respond to him directly.

In it, he calls Trump an "existential threat to America." That was part of his effort to emphasize the economy— an issue the president often promotes as his chief strength in a time of low unemployment — during a speech in Davenport, a center of eastern Iowa's agricultural manufacturing industry.

"How many sleepless nights do you think Trump has had over what he's doing to America's farmers?" Biden will ask, according to the prepared remarks. "Zero."

Though the race for the Democratic nomination is early and fluid, the dueling visits to Iowa offer a glimpse into what a Trump-Biden matchup might portend. Trump and Biden have been circling each other for months .

Despite the private counsel of his advisers, Trump had thrown a steady stream of public insults at Biden even before his fresh round Tuesday. Since March, Trump has mocked or criticized Biden on Twitter nearly 40 times.

In one of his most brazen attacks, during a recent state visit to Japan , Trump echoed North Korean leader Kim Jong Un's description of Biden as "low-IQ."

Biden, in turn, has hit at Trump. At a recent Houston fundraiser, Biden vowed not to "get down in the mud wrestling with this fella," only to say later at the same event, "We all know this guy doesn't know anything."

Both men have something to prove during this trip.

For Trump, the biggest concern in this state dominated by agriculture interests is trade. He begins his trip in Council Bluffs to tour and speak at Southwest Iowa Renewable Energy, which produces and sells the corn-based fuel additive ethanol, before addressing an Iowa GOP dinner in Des Moines.

He's expected to highlight his efforts to help farmers hurt financially from Chinese tariffs on U.S. agriculture products, measures that were imposed last year after Trump slapped levies on Chinese imports.

Trump also is likely to try to sell farmers on the U.S.-Mexico-Canada trade deal, which remains to be ratified by lawmakers in each country. Supporters of the deal, which is an update to the North American Free Trade Agreement, feared that Trump's recent threat to impose tariffs on Mexico over illegal immigration would jeopardize the pact's passage by U.S. lawmakers. But Trump announced an agreement with Mexico late last week and delayed the tariffs for the time being.

The president, however, has been stung by criticism that what he announced Friday resembled steps Mexico had already agreed to take. He lashed out Monday in a pair of tweets in which he teased a secret deal with Mexico to be announced soon. Mexico countered that no secret deal was in the works.

For his part, Biden's trip comes after he roiled the Democratic contest last week by saying he supported a prohibition on federal funds supporting abortion. After an outcry from women's groups and most other Democratic candidates , he backtracked and said he would support the repeal of the Hyde Amendment.

On the weekend, more than a dozen of Biden's Democratic rivals were in Iowa for a party dinner. Several aimed veiled barbs at the former vice president for skipping the event and framed him as someone unable to bring the country into the future.

According to his prepared remarks, Biden will say he was at his granddaughter's high school graduation.

"I guess some folks were surprised I made that choice, but I don't know why," he will say. "There are some things more important than running for president."

Superville reported from Washington. Associated Press writers Alexandra Jaffe in Dubuque, Iowa, and Zeke Miller in Washington contributed to this report.