Libertarian Rick Breckenridge threw Montana’s U.S. Senate race into a frenzy Wednesday by endorsing the Republican contender, although his name remains on the ballot and any votes cast for him will not be transferred to Matt Rosendale.

That was the word from the Secretary of State’s Office, where elections director Dana Corson said he has received no official notification that Breckenridge is ending his candidacy.

Even were that notice to come, it would not change Breckenridge’s status in Tuesday’s voting, Corson said.

He was, however, going to double-check the law with experts in the election office.

Breckenridge made the surprise announcement Wednesday morning in a conference call with reporters, saying he became concerned after seeing a flier – apparently paid for by a dark-money group – touting him as the “true conservative” in the race.

The mailer also accused Rosendale of supporting the use of drones to spy on American citizens.

"I'm not going to take the seat, and so I'm here today to support Matt in his candidacy, and endorse him," Breckenridge said during the conference call with reporters from Montana Public Radio and other state and national media outlets.

He repeated the assertion in an interview with the Associated Press.

Rosendale, in turn, thanked his Libertarian challenger for the endorsement with this statement:

“I am honored to have the endorsement of Rick Breckenridge. I share his concerns with veterans issues and access to health care, and the need to limit the role of government in our lives. Rick is one of the most honest and principled men I’ve come to know, and I appreciate the Republican and Libertarian Parties unifying in Montana to defeat Jon Tester this November.”

Should Breckenridge’s supporters actually cast their ballots for Rosendale, they could conceivably swing the election in the Republican candidate’s favor.

Recent polls have shown Rosendale and Democratic incumbent Sen. Jon Tester in a dead heat with the critical midterm elections less than a week away.

A Gravis Marketing poll released this week showed Tester leading by 3 percentage points, with a margin of error of 3.5 percent.

The national Republican Party is pulling out all the stops in an effort to knock Tester out of the Senate, including an unprecedented fourth campaign stop in the state – this Saturday in Bozeman – by President Donald Trump.

Tester drew the president’s ire earlier this year when he blocked confirmation of Trump’s original nominee for Secretary of Veterans Affairs, Ronny Jackson, over questions of his personal and professional conduct.

In Tester’s last re-election bid, the Libertarian candidate – Dan Cox – may have siphoned votes away from Republican Denny Rehberg, who lost the race by 4 percentage points. Cox picked up 6 percent of the vote in the 2012 race.

That year, a similar dark-money mailer encouraged conservatives to vote for Cox rather than Rehberg.

This year, polls have shown Breckenridge pulling between 2 percent and 4 percent of the vote, although there’s no way to know how many of those voters would otherwise side with Tester or Rosendale.

In a debate earlier this season with the two mainstream party candidates, Breckenridge sided with Rosendale on some issues, with Tester on others, and with neither of his competitors on others.

In particular, Breckenridge disagrees with Trump’s plan to build a wall along the southern U.S. border – a strategy backed by Rosendale.

And Breckenridge agreed with Tester’s concerns about Brett Kavanaugh’s nomination and eventual confirmation to the U.S. Supreme Court, citing the justice’s opinions on privacy issues.

But on Wednesday, Breckenridge was all in for Rosendale, calling him “the front man in the cause of liberty.”