U.S. Rep. Steve King, who has long courted controversy, has now courted a new opponent: a prominent Republican challenger will vie against him in 2020.

Iowa Sen. Randy Feenstra, who helped lead an effort last year to approve massive tax cuts in Iowa, said Wednesday that he'll seek the GOP nomination for King's 4th Congressional District. King won re-election two months ago, after an unusually close race for the longtime House member.

Feenstra, of Hull, did not mention King by name in his emailed announcement but tacitly acknowledged the staunch conservative member of Congress, who's made offensive remarks on immigration, multiculturalism and other issues. King has previously dismissed the criticism.

“Today, Iowa’s 4th District doesn’t have a voice in Washington, because our current representative’s caustic nature has left us without a seat at the table,” Feenstra said in a statement. “We don’t need any more sideshows or distractions, we need to start winning for Iowa’s families.”

King says Feenstra is 'easily swayed by the left'

King, of Kiron, has not indicated publicly whether he'll seek re-election in 2020, but he didn't hold back his feelings about Feenstra's run. An emailed statement sent by Jeff King, the congressman's son and employee, began by claiming that Feenstra told Jeff King in late December that he "would never" run against the elder King.

Steve King's statement added: "Today, misguided political opportunism, fueled by establishment puppeteers, has revealed that Mr. Feenstra is easily swayed by the lies of the left."

King has faced other primary challengers since getting elected to the northwest district in 2002. King noted that history in his statement, calling Feenstra's bid an "attempt by the establishment in as many primary cycles to take the 4th District out of the hands of grassroots Republicans."

King's statement, which highlights that President Donald Trump has called the congressman "the world’s most conservative human being," concludes that Feenstra "offers Republican voters nothing but warmed over talking points from liberal blogs and failed Democratic candidates.”

Republican official don't promise to support King

But Feenstra's announcement could be the beginning of a serious political fight for King. Feenstra has hired consultant Matt Leopold to help run his campaign. Leopold served as political director on Gov. Kim Reynolds' recent gubernatorial campaign during the primary.

Reynolds — who named King as a campaign co-chair during her election — would not endorse King during an interview Wednesday with a local television station. She said she wouldn't weigh in on a primary.

"The last election was a wake-up call for it to be that close," she told WHO-TV. "That indicates that it does open the door for other individuals to take a look at that."

Reynolds was referencing the fact that while the congressman was able to fend off an election challenge from Democrat J.D. Scholten, it was his closest race since his first election.

Nov. 6 appears to have put King on defense. He announced earlier this month that he will hold town halls in every county in his northwest district, a change from recent years.

U.S. Sen. Chuck Grassley was noncommittal on Wednesday about his thoughts on Feenstra or any other primary challenger.

"It’s very rare for me to get involved in a primary, so any Iowan in office today where I say, 'I’m not getting involved in a primary,' they shouldn’t take it personal," the Republican senator said.

Jeff Kaufmann, chairman of the Republican Party of Iowa, offered a similar response in a statement: “As we are in all legitimate primary contests, the Republican Party of Iowa will remain neutral in this race. The good people of the fourth district will have the ultimate say.”

Democrats don't like King or Feenstra

Iowa Democrats don't like King or Feenstra. Iowa Democratic Party Chair Troy Price said in a statement: "The 4th District deserves a public servant who will put the people’s interests ahead of political ambitions, but, unfortunately, that’s not Sen. Feenstra."

In Feenstra's announcement, he expressed wanting to provide Trump "with a strong voice who can help protect and advance a conservative agenda for America."

Feenstra was critical of Democrats with their new majority in the House. House Speaker Nancy Pelosi has been in the midst of negotiations with legislative leaders and Trump to end a partial government shutdown over immigration that's stretched into more than two weeks. Trump wants $5.7 billion for a wall along the U.S. southern border with Mexico. Democrats do not support that funding, in part by noting that Trump had promised Mexico would pay for such a structure.

“What we’ve seen this past week from the new Democratic majority in Congress is appalling. ... The President needs effective conservative leaders in Congress who will not only support his agenda, but actually get things done," Feenstra said.

Feenstra was elected to the Iowa Senate in 2008. He is currently the head of the powerful tax-writing Senate Ways and Means Committee.