Tester knows what he’s doing. Manchin doesn’t. Maybe Manchin should have kept his mouth shut instead of showboating with Kyrsten Sinema. He might not have found himself in this position: Sens. Jon Tester of Montana and Joe Manchin of West Virginia are expected to face among the toughest political environments as the Democratic Party attempts to hold the Senate next year, given that the two incumbents hail from states where President Joe Biden performed poorly against then-President Donald Trump in 2020. But the Montanan is beginning the cycle with a huge popularity advantage, while Manchin remains among the country’s most unpopular politicians — fraught territory in the face of an expected challenge by his state’s popular Republican governor, Jim Justice, according to the Morning Consult’s latest quarterly approval ratings. Surveys conducted between Jan. 1 and March 31 show that 58% of Montana voters approve of Tester’s job performance, making him one of America’s most popular senators. In West Virginia, Manchin’s standing appears in the inverse, with 55% of voters giving him negative marks — landing him again among America’s most unpopular senators. Tester’s approval rating steadily improved in 2022, while Manchin’s standing plummeted after he agreed to support Biden’s Inflation Reduction Act. Since then, Manchin’s approval rating has continued to decline despite his best efforts to distance himself from national Democrats. Tester agreed to the Inflation Reduction Act too. He just didn’t present himself as a power broker to the whole country and draw attention to himself like Manchin did.…