West Des Moines—Nikki Haley criticized Democratic-controlled Washington on Thursday evening as she outlined her vision for the Republican Party and banked political favors in a key state ahead of a possible 2024 presidential bid.

A critic of former President Donald Trump before becoming his United Nations ambassador for two years, Ms. Haley headlined the Republican Party of Iowa’s biggest gathering of the year. Her speech to about 500 people, which received a standing ovation at its conclusion, focused more on the current president than his predecessor.

“ Joe Biden has been a gift to every country that hates America and wants to hurt us. He’s the polar opposite of Donald Trump,” she said. “I saw firsthand as ambassador to the United Nations how Donald Trump put America first—sometimes in the most interesting of ways.”

The former South Carolina governor said the party needs to balance toughness with respectfulness.

“Republicans are too nice,” she said. “I wear heels—it’s not for a fashion statement—I use them for kicking. But I always kick with a smile.”

Ms. Haley, who is spending three days in Iowa as part of traveling the nation to help Republicans raise money for next year’s midterm congressional elections, kept her remarks focused on 2022 goals.

“This Republican Party and the American people will take back our country from Joe Biden and the radical left,” she said. “Today’s Democrats don’t just blame America. They don’t even believe in America. And that’s why they don’t deserve to lead America.”

Two spokesmen for the White House didn’t respond to an email seeking comment.

Ms. Haley suggested that her party needs to reconnect with its roots.

“We are not the party of woke corporations,” she said. “We are not the party of taxpayer bailouts and government dependency. The Republican Party stands for economic freedom. Capitalism is economic freedom and we should never apologize for it.“

Ms. Haley’s Lincoln Dinner appearance, a high-profile stop in the state that is expected to host the first GOP presidential nomination balloting in 2024, gave her a chance to introduce herself to activists and offer contrition to supporters of Mr. Trump that she may have offended in the past.

Earlier this year, Ms. Haley told Republican National Committee members that Mr. Trump would be “judged harshly by history” for his behavior after November’s election. She also told Politico she didn’t think the former president was going to be “in the picture” when it came to the party’s future because he had “fallen so far.”

Ms. Haley has since softened her tone, telling reporters in April that she won’t embark on a 2024 White House bid if Mr. Trump decides to run again. Her back and forth regarding the former president has left some questioning Ms. Haley’s political compass.

“She is ambitious and capable, but I think she suffers from the disease of not knowing what lane she is in,” said Doug Gross, a Des Moines lawyer and Republican political operative who has held Iowa leadership roles for past presidential campaigns. “You have to decide who you are.”

Ms. Haley’s spokeswoman declined to comment on that criticism, but offered a statement in response.

“Iowa is a top target for D.C. Democrats in 2022,” said Chaney Denton. “Ambassador Haley’s priority is taking back the House and Senate and electing conservatives up and down the ballot.”

On Friday, Ms. Haley is slated to visit a central Iowa farm for a lunchtime event that is expected to attract 50 to 100 people, including some younger Republicans. She will also attend fundraisers benefiting the state’s governor, two members of Congress and Iowa House Republicans during her trip.

In a straw poll conducted as part of last weekend’s Western Conservative Summit in Denver, Ms. Haley ranked 13th for support among potential GOP presidential candidates in the still-unformed field. The unscientific survey had Florida Gov. Ron DeSantis as the most-liked, slightly ahead of Mr. Trump.

Mr. Gross, who is skeptical that Mr. Trump will run again, said he expects a large number of potential candidates to make Iowa trips in the coming months under the cover of campaigning for state and congressional candidates ahead of next year’s midterm elections. “Everyone will try to be in the Trump lane and there will be one lane for a non-Trump person,” he said.

Mr. Trump has said he is unlikely to reach a final decision about a third White House campaign until after the midterms, contests where he intends to play a key role handpicking candidates and punishing those who have crossed him. He is scheduled Saturday to hold his first campaign-style rally since leaving office, an event in northern Ohio sponsored by his Save America political-action committee.

A Quinnipiac University poll released late last month showed roughly two-thirds of Republicans would like to see Mr. Trump run again, while about two-thirds of Americans overall don’t want him to make another White House bid.

Ms. Haley’s appearance is the first in a series of coming Iowa visits by possible GOP presidential candidates. Sen. Tom Cotton of Arkansas is scheduled to travel next week to one of the state’s most conservative counties, while former Vice President Mike Pence, Gov. Kristi Noem of South Dakota and former Secretary of State Mike Pompeo will speak at a mid-July event sponsored by an influential organization of social conservatives.

While the visits might seem early, they aren’t by historical standards. Sen. Marco Rubio of Florida, another potential 2024 Republican candidate, traveled to Iowa less than two weeks after the 2012 presidential election ahead of his unsuccessful 2016 White House bid.

Scott Henry, whose family is hosting Ms. Haley on their nearly 10,000-acre farm in central Iowa, said he would like to see the GOP move beyond Mr. Trump.

“There are a lot of good things that Trump did, but at the same time there are other people who can carry the torch for this party,” said Mr. Henry, who voted for Mr. Trump in 2016 and 2020. “There is an opportunity for us as a party to restore some of the statesmanship, while still not disenfranchising people who think Trump is the only person who understands their views.”