Two longtime DFL state senators from the Iron Range severed ties with their party on Wednesday, forming an independent caucus and altering the dynamics in a narrowly divided Minnesota Senate.

Sen. Tom Bakk of Cook, a former DFL leader at the Capitol, and Sen. David Tomassoni of Chisholm cited growing political polarization and an opportunity to chair committees and better serve their districts within the legislative framework as reasons for the split.

“I’m very disappointed by the extreme partisanship going on nationally and right here in Minnesota,” Bakk said in a statement, first reported by KSTP and MPR News. “Both political parties are to blame. The constant negative and sharp rhetoric is undermining voters’ confidence in our public institutions. It doesn’t have to stay this way.”

The public split comes amid a deepening ideological and geographic divide in the Democratic Party both in Minnesota and across the country. Democrats racked up significant wins in urban and suburban areas Nov. 3, but Republicans extended their dominance in many rural areas, particularly large swaths of northern Minnesota.

Bakk had led the Senate DFL caucus for nearly a decade and was first elected to the chamber in 2002, after serving in the House for eight years. He also served as chairman of the influential Senate taxes committee, which made him crucial to nearly every facet of legislative negotiations. He was a driving force behind passage of the new Minnesota Vikings stadium.

A former gubernatorial candidate, Bakk has frequently clashed with powerful DFLers, including former Gov. Mark Dayton and then-House Speaker Paul Thissen during a budget showdown.

More recently, Bakk has been at odds with many DFLers over his strong support for expanded copper-nickel mining on the Iron Range.

In February, he narrowly lost the Senate DFL leadership post to Sen. Susan Kent of Woodbury.

“The Senate DFL caucus includes a broad spectrum of views, especially as the only senate caucus with members from urban, suburban, and greater Minnesota communities,” Kent said in a statement. “But it does not stretch as far as those who wish to function outside of our values as a caucus.”

Tomassoni was elected to the House in 1993, and to the Senate in 2001. He has been a strong backer of plans to expand mining across the Iron Range, a view shared by many Republicans. He has spent much of his political career focused on economic development, particularly in northeastern Minnesota.

Senate Republicans were already set to hold a slim advantage in the upper chamber after the election.

The decision means that instead of a 34-33 split in the GOP-led chamber, the Senate will be composed of 34 Republicans, 31 Democrats and two independents. Democrats have a House majority.

GOP Senate Majority Leader Paul Gazelka welcomed the announcement.

“We share the same vision of a prosperous Iron Range and will continue to work with them to fight for jobs on the Range,” the East Gull Lake Republican said.

The shift could bolster their strength if Bakk and Tomassoni vote more often with the GOP. Those extra votes could give Gazelka leeway to pass a budget and other legislation, even if not all members of his own caucus are on board. Absences or retirements could be less of an issue as Republicans try to shore up votes to pass controversial measures.

“What this really means is this now effectively gives Republicans not just a one-vote margin but a fairly significant margin,” said David Schultz, a political-science professor at Hamline University.

In the state Legislature, the few remaining Democrats from the Iron Range and rural areas regularly break with metro counterparts on issues such as mining, the environment and DFL Gov. Tim Walz’s pandemic restrictions.

The results of the Nov. 3 election further cemented the urban-rural divide, with Democrats in both chambers losing seats in Greater Minnesota.

“In lots of ways, the Democrats are really being reduced now to a few urban areas, the Twin Cities, Olmsted County, maybe eventually Dakota County,” Schultz said. “It’s a very small number of counties geographically they represent at this point. A lot of people, but not a lot of land.”

The announcement follows another unusual political partnership between Tomassoni and the Senate Republicans. Last week, the longtime legislator was voted in as temporary Senate president as part of a gambit by the GOP to protect its slim majority should U.S. Sen. Amy Klobuchar join the Biden administration.

The move was meant as a safeguard against a scenario in which Walz appoints Lt. Gov. Peggy Flanagan to Klobuchar’s seat. If that happened, the Senate president would be elevated to the lieutenant governor post, leaving a vacancy in the chamber.

In remarks last week, Tomassoni urged collaboration as he noted that he was the first member of a minority party to serve as Senate president.

The formation of new caucuses isn’t unheard of at the Capitol. Four former House Republicans split from their GOP counterparts to form the New House Republican Caucus in late 2018.