U.S. Rep. Erik Paulsen and DFL challenger Dean Phillips clashed over health care, tax reform, immigration and other issues, trading barbs Tuesday in the first debate of their increasingly heated fight for a Minnesota House seat.

The debate at a St. Louis Park hotel quickly grew testy, with both candidates attacking the other almost immediately. Paulsen, a Republican, referenced Phillips’ personal wealth when he said that people who are not millionaires should be able to run for Congress, while Phillips pressed Paulsen to reject campaign donations from interest groups and hit him for voting for most of President Donald Trump’s agenda.

“I’ll stand up to my own party,” Paulsen said, whether that’s protecting the Boundary Waters Canoe Area Wilderness, opposing “misguided tariffs” or pushing for a vote on immigration legislation.

Phillips said that rings hollow, citing a tally by the website FiveThirtyEight that currently has Paulsen voting with Trump’s position 98 percent of the time.

“I don’t believe Congressman Paulsen represents the principles and values of our district any longer,” said Phillips, who has pledged not to accept campaign donations from political action committees that represent business, unions or other groups.

The battle for the Third Congressional District — which stretches across much of the west and northwest metro and includes suburbs from Bloomington to Minnetrista to Rogers — is shaping up to be one of the nation’s most competitive House races. And it is one of Minnesota’s most expensive fights, as a first-time political candidate tries to unseat Paulsen, a Republican who has repeatedly won re-election by wide margins since taking office in 2009.

Money is taking over politics, Phillips said, and changing that would be his top priority if elected.

“I will be the loudest voice for campaign finance reform that the U.S. Congress has ever seen,” said Phillips, a businessman and Phillips liquor fortune heir.

Paulsen called his opponent “hypocritical,” and said Phillips has spent more on his campaign than the thousands he mentioned at Tuesday’s event. A five-term congressman, Paulsen instead tried to focus on cases where he worked with Democrats — talking about bipartisan bills he backed and trying to distance himself from Trump, as he seeks to win a congressional district that went for Democrat Hillary Clinton in 2016.

On immigration, one of the most controversial issues in this election cycle, Paulsen said he is trying to find a middle ground. The immigration system is broken, he said, and he wants to change the visa lottery process to prioritize skilled workers over family connections. He said young immigrants known as Dreamers should stay in the U.S., adding “for all practical purposes, they are America’s children.”

Phillips said Congress should pass comprehensive immigration reform and the country should provide a path to citizenship for anyone in the U.S. who is working toward it. He called Trump’s border wall proposal un-American and a terrible use of money.

He favors changing immigration laws over the creation of so-called sanctuary cities or states, where restrictions limit how local authorities work with federal immigration enforcement. Paulsen was firm in his opposition to sanctuary cities, adding that Immigration and Customs Enforcement’s work is important to prevent drug and human trafficking.

The candidates were particularly divided over health care. Phillips wants to expand Medicare and offer a buy-in option for everyone. He proposed addressing the high cost of health care by reforming how care is delivered through incentivizing preventive and quality care rather than rewarding procedures and hospitalization.

Paulsen previously voted to repeal and replace the Affordable Care Act, which he said “destroyed Minnesota’s health care.” He said the Medicare For All idea many Democrats are calling for is very expensive and would add to the national debt.

“I want to make sure we are protecting and preserving Medicare,” Paulsen said, instead of opening it up for broader use, which he said would hurt seniors.

Paulsen highlighted his work on the tax reform bill that passed last year, and said it has helped expand the economy and create more jobs. There are pieces of the tax bill Phillips said he would like to see continue, but overall he said the middle class did not get a good deal and he would push for reforms.

“We’ve got to manage our fiscal house more thoughtfully than we are right now,” Phillips said, adding that the tax bill “explodes” the national debt.

The debate, hosted by the TwinWest Chamber of Commerce, followed jabs from both sides over how best to engage voters. Tuesday’s event has been scrutinized for its price tag of $60 for non-chamber members. The event was reservation-only and didn’t take questions from the audience. The room included a big crowd of Phillips supporters, who often hissed at Paulsen, and gave Phillips a standing ovation at the end of the debate.

Echoing progressive activists, Phillips has pushed for free public debate. He invited Paulsen to join him at a series of public voter forums he is holding around the district. Paulsen’s campaign responded Tuesday by instead proposing three moderated, ticketed debates where each of the campaigns would be given half the tickets to distribute as it wished.

Paulsen said at Tuesday’s event that he expects they will have more debates as the election season continues.

The Cook Political Report currently deems the race a tossup, while FiveThirtyEight’s Nate Silver predicts a 61 percent chance of Phillips winning. But Phillips doesn’t have history on his side. The Third District has been electing Republicans to Congress since 1961.

Star Tribune staff writer Kelly Smith contributed to this story.