Trump campaigns in same Iowa city DeSantis visited Friday

Donald Trump held a campaign event in Davenport, Iowa, on Monday, just three days after Florida GOP Gov. Ron DeSantis -- widely expected to be the former president's toughest opponent for the GOP nomination -- spoke before a standing-room-only crowd of several hundred in a casino room in the same eastern river town.

"I think we're going to do fantastically here," Trump said at his Monday event. "I made those promises to the people of Iowa and America and I kept every single one of my promises and now we're laying out a bold forward-looking vision for what we will do. When we take the oath of office and we get back that beautiful, beautiful White House and we become together the 47th President of the United States."

"Within hours of my inauguration, I will cancel every Biden policy that's brutalizing our farmers," he said.

It was Trump's first visit to the Hawkeye State since he announced his 2024 White House bid in November, but it's hardly his first time in the critical early-nominating state. Now embarking on his third presidential bid, Trump has over the past eight years hosted a number of rallies, and takes credit for moving the formerly reliable purple state to a "reliable MAGA stronghold."

"President Trump's America First Policies continue to resonate with the men and women of Eastern Iowa and will propel him to an overwhelming victory in the First-in-the-Nation Caucuses," his campaign said in an email ahead of his stop.

On Friday, DeSantis, still undeclared, launched his first Iowa swing of the 2024 presidential cycle -- followed by a Saturday visit in the early-voting state of Nevada and ahead of a scheduled New Hampshire stop, all while he's privately indicated to allies he intends to launch his candidacy in May or possibly June, sources familiar with his plans told ABC News.

Trump addressed DeSantis' political fortunes with a group of reporters on en route to Iowa on Monday, saying he regretted endorsing DeSantis for governor in 2018, saying, "This guy was dead. He was dead as a doornail … I might say that," Trump told Politico.

"I said, 'You are so dead right now you are not going, no endorsement is going to save you. George Washington won't save you.' He said, 'I'm telling you, if you endorse me, I have a chance,'" Trump said.

Trump lambasted DeSantis over his previous support -- while serving in Congress in 2017 -- of a bill that would have immediately ended the Renewable Fuel Standard, which mandates that specific percentages of renewable fuel be part of the nation's fuel supply.

Ethanol, a major industry in Iowa, is a key issue for many of the state's farmers.

"Okay, so remember this -- Ron Desanctus ... Desanctimonious ... Ron Desanctus strongly opposed ethanol. Do you know that? And we don't even know if he's running but I might as well tell you. If he's not running, I'll say he was fine on ethanol, don't worry," Trump said in his speech.

"He strongly opposed ethanol and fought against it at every turn. And he's gonna do that again. Because people that come out early for something, that's where they go. Politically, but he was very, very bad on ethanol. He bought it all the way and he also fought against social security," he said.

Trump himself faced criticism from farmers while president because he granted ethanol waivers to some small refineries, giving them an exemption from blending ethanol into their fuel.

Trump addressed his education priorities, which include allowing parents to vote for school district principals, ending vaccine mandates in schools, barring transgender females from participating in women’s sports and breaking up the federal Department of Education and redistributing its functions to the states.

“I was getting ready to do it -- pull the trigger. The long-term goal, but now it's a short-term goal,” Trump said.

On Friday in Davenport, DeSantis touted his stance on Florida education, which he said was based on "educating our kids not indoctrinating our kids."

The governor pushed his sweeping conservative agenda that includes prohibiting higher education institutions from using any funding to support Diversity Equity Inclusion or Critical Race Theory.

"We're also leading on ensuring that our school system is focusing on educating our kids not indoctrinating our kids," DeSantis said.

"And also, university wide our whole system. The legislature is working on a redesign. We're eliminating all of the DI bureaucracies. It's discriminatory …"We will fight the woke in the legislature we will fight the woke in education. We will fight the woke and the businesses we will never ever surrender to the woke mob. Our state is where woke goes to die," he said.

The topic is a winning issue with Iowa Republicans, as GOP Gov. Kim Reynolds has repeatedly touted her leadership among members of the GOP in the area of education. DeSantis sat down for conversation with during his Iowa sweep last week.

Reynolds was one of the first of a growing faction of Republican governors who have embraced school voucher programs, which critics warn could destroy their states' public school systems.

Trump also expressed his support for universal school choice.

“I want to congratulate Iowa on recently becoming the second state in the nation to deliver universal school choice,” Trump told Reynolds.

As they lead in early Republican primary polls, Trump and DeSantis' dueling events in Iowa could indicate their respective shows of force. Trump remains a frontrunner in the race among Iowans, though his lead over confirmed and expected challengers in polls has waned in recent months.

"How the hell would I lose Iowa? How is that possible? And then I got a poll the other day that was way up," Trump said in Davenport on Monday.

On Friday, just days ahead of Trump's Monday visit, a a new Des Moines Register/Mediacom Iowa Poll found that if former President Donald Trump were to be the Republican nominee again 74% of Iowa Republicans say they would likely vote for him in the 2024 general election -- although the number of Iowans who say they would "definitely" vote for him has decreased by more than 20 percentage points since June 2021.

But the poll also found that Desantis' favorability numbers were on par with Trump's–just two points behind the former president.

But Trump's laser-like focus on Iowa kicked off Monday ahead of his Davenport visit with an announcement of his Eastern Iowa leadership team "demonstrating support from the most conservative and influential Republican leaders in a key region of the Hawkeye State," his campaign email said.

The slate of legislative endorsees include Matthew Whitaker, the former acting attorney general under President Trump; Rod Blum, a former congressman from Iowa; and state Rep. Bobby Kaufmann, the son of Iowa GOP Chair Jeff Kaufmann, among others.

Trump's visit also comes as there are multiple criminal and civil investigations still actively probing his personal finances, his handling of classified information after leaving the White House, his namesake business, and his efforts to overturn the results of the 2020 presidential election.

These investigations in several jurisdictions around the country are continuing to move forward, with numerous key developments unfolding in recent weeks.

ABC News' Olivia Rubin, Rachel Scott, Katherine Faulders, John Santucci, Alex Mallin and Will Steakin contributed to this report.