One of the greatest strategic minds in history, Napoleon Bonaparte warned never to interrupt your enemy when he is making a mistake. The Democrats are weighing their options on primarying a popular U.S. senator in a purple district that President Donald Trump has won twice. Should they go through with it, the GOP has an almost guaranteed pickup of a Senate seat.

Democratic Pennsylvania Sen. John Fetterman’s approval rating is struggling among his party’s voters, likely because of his moderate stance on issues important to blue-collar workers. However, Independents and Republicans are widely supportive of his work in the Senate. To win the seat, Democrats also need to appeal to these voters.