Cook moved Senate races in Montana, Nebraska and New Jersey all in favor of Republicans. Sen. Jon Tester (D-Mont.) faces one of the most competitive race this cycle, which was shifted from “lean Democratic” to “toss-up.” Tester is running against state auditor Matt Rosendale (R) in a state where President Trump won by double-digits in 2016.
Jennifer Duffy, a Senate race analyst at Cook Political Report, said Tester initially looked likely to sail to reelection with a comfortable lead in polling and Rosendale facing a crowded primary. Duffy noted that the fight over Supreme Court nominee Brett Kavanaugh’s nomination is energizing the GOP base, though she still gives Tester a slight advantage in the toss-up race.