The Cook Political Report shifted the Montana Senate race from “toss up” to “lean Republican” on Thursday as polls show Republican Tim Sheehy leading incumbent Sen. Jon Tester (D) in a contest critical to control of the upper chamber.

The nonpartisan prognosticating group made the move with less than two months before Election Day, giving Republicans a shot in the arm in the process 

“Today we are making a major shift --- moving the Montana Senate race from Toss Up to Lean Republican,” the Cook Political Report’s Jessica Taylor wrote. “This means that Republicans are now an even heavier favorite to win back control of the Senate, regardless of the result at the top of the ticket.”

Republicans need to flip only two seats in order to win back the majority that has eluded them for four years. The West Virginia seat currently occupied by retiring Sen. Joe Manchin (I-W.Va.) is a virtual certainty to go to the GOP, with Gov. Jim Justice (R) is in line to replace him. 

That leaves Republicans needing one seat, with Montana serving as their best chance.

According to a recent AARP poll, Sheehy leads the three-term incumbent by 6 percentage points. He also clears the all-important 50 percent threshold in the survey. 

The Senate GOP campaign arm also told members at a luncheon earlier this week that internal polling shows Sheehy leading by 4 percentage points. 

Senate Republicans are also hopeful Bernie Moreno will defeat incumbent Sen. Sherrod Brown (D) in Ohio, but that race is widely considered a jump ball. 

The Cook Political Report rates both Ohio and Michigan — where Rep. Elissa Slotkin (D-Mich.) and former Rep. Mike Rogers (R-Mich.) are running to replace Sen. Debbie Stabenow (D) — as toss-up races. 

Contests in Pennsylvania, Nevada, Wisconsin and Arizona are all rated “lean Democrat.”