The seven most competitive Senate races this year are seats now held by Democrats (or, in one case, a Democrat-turned-independent). Democrats will need to retain them all to keep control of the chamber. Most of these seven are in swing states (Michigan, Wisconsin, Pennsylvania, Arizona and Nevada). Ohio and Montana are where Democrats will have their work cut out. Mr Tester’s job will be the hardest. He will have to persuade voters in a state that Mr Trump won by 16 points in 2020 to send a Democrat to represent them in Washington. An average of recent polls suggests that he is running roughly three points behind Tim Sheehy, his Republican opponent. It is worth noting, however, that a number of these polls are from Republican, or Republican-leaning, pollsters.