AMNA NAWAZ: With just six weeks until the first-in-the-nation Iowa caucuses, several Republican hopefuls made stops in the Hawkeye State this weekend.

Lisa Desjardins begins our coverage.

LISA DESJARDINS: Ron DeSantis all in on Iowa.

GOV.

RON DESANTIS (R-FL), Presidential Candidate: Iowa will begin the revival of the United States of America.

(CHEERING AND APPLAUSE) LISA DESJARDINS: As the Florida governor fights for his political survival, he finished his tour of all of the state's 99 counties on Saturday.

Inside the Thunderdome restaurant in Newton, DeSantis' political jabs at his opponent and GOP front-runner, Donald Trump, were muted.

GOV.

RON DESANTIS: I have been very frank with my views on President Trump's campaign, where he's campaigning on things that he promised to do in '16 and didn't deliver.

But I have also acknowledged the good things that were done.

LISA DESJARDINS: Trump has been in Iowa far less than his opponents, but that hasn't mattered to GOP voters.

He has a seismic 40-point lead.

He focused on the state this weekend with two rallies, mocking DeSantis for those poll numbers.

DONALD TRUMP, Former President of the United States (R) and Current U.S. Presidential Candidate: He's been falling out of the air like a very seriously wounded bird, right, to the ground.

LISA DESJARDINS: And the former president continued to spout the lie that he won the 2020 election.

DONALD TRUMP: They rigged and stole the election of 2020.

They rigged it and they stole it.

LISA DESJARDINS: Even as Trump faces state and federal indictments for his efforts to overturn the legitimate results of the election that President Biden won, and his sharpest attacks hit at the Democratic front-runner, with Trump trying to flip his own vulnerability.

DONALD TRUMP: Joe Biden is not the defender of American democracy.

Joe Biden is the destroyer of American democracy.

LISA DESJARDINS: He again alleged without evidence that President Biden has weaponized the Department of Justice to bring criminal cases against him.

While Trump continues to hold a commanding lead in GOP polls, Nikki Haley has been on the rise in recent weeks, jumping into second place in New Hampshire and South Carolina and tying for second in Iowa.

And just days ago, the former South Carolina governor began running her first TV ad in the early states.

NIKKI HALEY (R), Presidential Candidate: It's time for a new generation of conservative leadership.

We have to leave behind the chaos and drama of the past and strengthen our country, our pride and our purpose.

WOMAN: I think our country would be very blessed to have Vivek.

LISA DESJARDINS: Vivek Ramaswamy's campaign launched an ad featuring his childhood piano teacher.

VIVEK RAMASWAMY (R), Presidential Candidate: We're going to deliver a major surprise.

LISA DESJARDINS: As the entrepreneur crisscrossed Iowa over the past few days.

Ramaswamy, DeSantis, and Haley will all be back in the Hawkeye State next weekend.

But, first, they will meet up for their fourth debate Wednesday night in Alabama.

For the "PBS NewsHour," I'm Lisa Desjardins.