It's very early, though I could see a scenario in which Tester is finally running out of luck due to increased political polarization, especially in a presidential year. Even if Biden wins reelection, he's not coming close in Montana. It requires Tester to outrun the top of the ticket by at least mid to high single digits.
This isn't unprecedented: Tester outran Obama by 17 points in 2012, while Bullock outran Hillary Clinton by 24 points in 2016. While it is true that Bullock only outran Biden by 6 points in 2020, the difference was that Bullock was running for reelection to his existing position in 2016 but was running for a new position in 2020, which greatly reduced his incumbency advantage in 2020 compared to 2016 (as I mentioned elsewhere in the forum, since 2014 the only Democrats to win statewide races in MT were those who were running for reelection to their existing positions, which applied to Bullock in 2016 and Tester in 2018; all other Democratic statewide candidates during this time were running for positions they hadn't yet occupied and thus fell short). Tester will have the advantage of being an incumbent running for reelection to his existing position in 2024, so that should be a factor in his advantage (I'm not saying Tester
can't lose, I'm just pointing out one of the reasons he should be counted out yet.).
It should be noted that there were a couple of polls in the 2018 cycle where Tester trailed Rosendale, so we should still wait for more polls to come out before definitively calling Tester an underdog and/or Rosendale a favorite.
