Des Moines, Iowa (CNN) President Donald Trump and former Vice President Joe Biden took their feud to the same state on Tuesday, holding dueling events in Iowa after spending weeks jabbing each other from a distance .

Biden, the 2020 Democratic candidate who has most consumed Trump, kicked off a three-stop swing by labeling Trump an "existential threat" to the country. It was just one of a series of blistering attacks the Biden campaign had previewed on Tuesday morning, and before even landing in the Hawkeye State, Trump began counter punching.

"His whole campaign is to hit Trump. When a man has to mention my name 76 times in a speech, that means he's in trouble," Trump said, before knocking Biden as a "dummy" and "weak mentally."

Trump's retort delivered exactly the kind of general election framing Biden has sought to elicit as he looks to solidify his front-runner status in a crowded Democratic primary. And despite repeated warnings from his advisers not to give Biden oxygen, Trump has continued to take the bait.

Trump will hold his first stop of the campaign season in Iowa Tuesday while Biden bashes him elsewhere in the state, but the President and former vice president won't come within 100 miles of each other while in the Iowa Tuesday.

Instead, the two will essentially draw an invisible line down the middle of it. Biden will spend his day campaigning in eastern Iowa, according to his schedule, while Trump will head for the western side to make remarks on renewable energy before flying to central Des Moines for a dinner and fundraiser with the state's Republican Party. White House officials insisted the twin visits to the state were not planned, but campaign aides said they found the optics humorous.

Though they won't come face-to-face, the feud that has bubbled up between Trump and Biden broke into public view as they prepared to share time in the state.

On Tuesday morning, Biden's campaign released his prepared remarks for later in the day, previewing a slew of blistering attacks on the incumbent he hopes to replace. And as Trump departed the White House, he fired a salvo of his own.

"His whole campaign is to hit Trump. When a man has to mention my name 76 times in a speech, that means he's in trouble," the President said, before suggesting that Biden -- who at 76 is about four years older than Trump -- has gotten "slower."

Trump, who has previously attacked Biden's intelligence, also called Biden "a dummy" and "the weakest mentally" among the field of 2020 Democratic candidates.

"I think he's the weakest mentally," Trump said. "And I like running against people that are weak mentally."

Trump's allies were delighted in recent days as the Biden campaign dealt with several missteps. Biden was hit with blistering criticism from his 2020 rivals over his position on an amendment regarding abortion rights, before reversing days later . His campaign moved quickly to amend their climate change plan after aides admitted several policy statements were missing attribution. And he skipped the largest gathering of 2020 Democratic presidential candidates to date while attending his granddaughter's graduation, a move that did not go unnoticed by his competitors.

But Biden will be in Iowa on Tuesday when Trump comes to town -- setting him up for the visual he has desired from the start: a direct competitor to the President.

"We didn't know Joe Biden was back from his hiatus," Tim Murtaugh, a Trump campaign spokesman, told CNN in a statement. "Has Alyssa Milano been consulted?"

The actress and women's rights activist has been a Biden supporter and reportedly urged him to reverse his stance on the abortion rights amendment.

Despite Biden's stumbles, those close to the President say Biden has occupied his head space more than any other candidate in the Democratic field, because Trump fears Biden poses a more serious threat to the blue-collar appeal that helped him win the 2016 election. Trump has continued to regularly phone aides and allies in the early morning hours to quiz them about Biden -- and ask whether he poses a threat to his staying power in the White House.

Trump lashed out in recent weeks after an internal campaign poll showed him lagging behind Biden in states that will be crucial to his re-election victory, such as Michigan, and even told some he doubted the numbers.

With his speech on Tuesday, Biden looked to damage Trump's support in those states and his image as a champion of working-class Americans, casting Trump's tariffs as harmful to farmers and manufacturing workers.

"Iowa farmers have been crushed by his tariff war with China and no one knows better than the folks in Iowa. He thinks that being tough is great, well it's really easy to be tough when someone else absorbs the pain: farmers, manufacturers, the automobile industry," Biden said.

Iowa as ground zero

For Trump, Iowa is among the collection of prized states that he turned from blue to red during his race for the White House. He carried Iowa's six electoral votes, defeating Hillary Clinton 52% to 42% , a staggering turnaround after Barack Obama twice won the state. In Iowa, 32 counties flipped between the last two presidential elections, where voters chose Obama in 2012 and Trump in 2016. It was more than any other state in the country.

Trump's visit on Tuesday serves as something of counter-programming for a state crowded with Democratic presidential candidates -- nearly two dozen of whom have been campaigning for the Iowa caucuses early next year. Trump, who has complained that Democrats are being treated more fairly by the press than he was, is intent on keeping the state in the Republican column in 2020.

Former Iowa Gov. Tom Vilsack, who served in the Obama administration as agriculture secretary, said Democrats underestimated Trump at their own peril.

"I think it would be foolish for anyone to assume that a sitting president is easily defeated," Vilsack told CNN. "I think we need to understand this is going to be a very, very difficult fight."

Barely a day goes by where one Democratic presidential candidate -- or several -- aren't visiting the state at any given time. Trump has become a frequent punch line, but Democratic leaders here have warned their supporters against thinking the President will be easy to unseat.

"You just can't bash him," said J.D. Schouten, one of the most sought-after Democratic leaders in Iowa who narrowly lost a congressional bid last year to Rep. Steve King, the outspoken conservative firebrand. "Democrats have to be for something."

Setting up a rivalry

While some aides have advised the President to refrain from attacking Biden by name, suggesting he "sit back and enjoy the show," others say Trump enjoys having a foil, no matter how far away the general election is. He has attacked Biden from the South Lawn of the White House, while standing next to the Japanese prime minister during a news conference in Tokyo and often from his favorite platform, Twitter.

And Biden, who is hoping to set himself apart from the fray of the expansive 2020 field, has happily returned the fire.

While in Davenport, Iowa, Tuesday, Biden will go after Trump by name dozens of times while labeling him "an existential threat to America."

"In 2020, we not only have to repudiate Donald Trump's policies and values -- we have to clearly and firmly reject his view of the Presidency," Biden will say, according to prepared remarks released by his campaign.

As the President grows more consumed with cable news coverage of his potential election foes, his campaign has focused on ways to distract from Democrats during their upcoming campaign rallies and election debates, aides told CNN.

But the President's re-election effort has noted he's not the only candidate on the ticket in 2020. His fundraiser Tuesday will benefit the Iowa Republican Party, not his campaign, an aide said. Tickets for the dinner started at $250 for general admission, with higher prices for a dinner with the president.

Trump spent a significant amount of time in Iowa during the 2016 presidential campaign. After he famously descended the Trump Tower escalator and declared he was running for president nearly four years ago, Trump boarded his 757 jet and headed straight for Des Moines, where he gave a wide-ranging speech and attendees received free "TRUMP: Make America Great Again" t-shirts.

He ultimately lost the Iowa caucuses to Texas Republican Sen. Ted Cruz, Trump but affirmed his support in the state when he beat Clinton in the general election. But two House seats in Iowa flipped from Republican to Democrat in the 2018 midterm elections, a sign of the state's continuing shifting demographics.