Republicans in Minnesota’s Second Congressional District on Saturday endorsed former conservative talk show radio host Jason Lewis to run for U.S. Congress.

Lewis is seeking the seat being vacated by Republican Rep. John Kline in one of the most closely watched congressional elections in the country.

Last week, DFLers in the district unanimously endorsed Angie Craig, a former executive at St. Jude Medical.

Lewis beat out remaining opponent David Gerson — who has previously lost to Kline — after the sixth ballot at the party’s convention in Apple Valley. After the final vote, Gerson pledged to back Lewis in an effort to keep the district red.

However, Lewis may still encounter challengers for the GOP nomination in the Aug. 9 primary. One such opponent will likely be Darlene Miller, a business leader who has come out strongly against the Affordable Care Act, taxes and what she calls government overregulation. Kline endorsed the political newcomer in March and said he continues to support her campaign.

On Saturday, Lewis called his victory a critical hurdle in overcoming Craig, whom he dubbed a “radical liberal.” Under his leadership, Lewis promised to defend the Constitution, simplify the tax code and help repeal President Obama’s signature health care law.

“The support of the grass roots is necessary to beat Craig and the national Democrat machine that is intent on dividing America,” Lewis said in a statement. “Together, we will challenge and defeat her campaign and its liberal agenda that is unaffordable, unsustainable and wrong for America and for the Second District of Minnesota.”

The Second District, the state’s only open congressional seat in the 2016 election, has become a battleground where Democrats believe they can finally win after Kline locked down the seat for 14 years. As Republicans have begun showcasing their conservative credentials, Kline has warned against alienating general election voters, calling the area a “swing district.” The district covers much of Dakota County, stretching south from St. Paul to Pine Island and east from Northfield to Wabasha.

Lewis’ endorsement drew strong reactions from DFL leaders, who have been highly critical of remarks he made on the air about young female voters and statements on slavery in his book on states’ rights.

In a prepared statement, DFL Chairman Ken Martin condemned Lewis as an “extreme right-wing Trump supporter” who is “extremely out-of-touch with the district’s families.”

“After a nasty primary when Republican candidates push each other even further to the right, the choice for the next representative from CD 2 is clear,” Martin said. “Angie Craig is the leader who looks for common ground and who will focus on the issues that matter to working families and should be elected to be their voice in Washington, D.C.”

Lewis recently told the Star Tribune that overflow crowds at GOP caucuses were responding to a “sense of urgency that the country is at a tipping point. … They’re looking at these precinct caucuses as where change begins and big government ends.”

He has vowed to support whatever presidential candidate wins the party’s nomination in July.