President Trump trails Democratic primary poll leader Joe Biden by four points in a new survey of Wisconsin voters, despite having an approval rating close to the 50% threshold that would suggest he is on track to win the critical swing state in November.

Scoring a repeat victory in Wisconsin is crucial to Trump’s reelection hopes. The Marquette University Law School survey issued Wednesday found that 48% of Wisconsin voters approve of the job Trump is doing, but that the former vice president leads Trump 49% to 45%. The poll of 800 registered voters, conducted Jan. 8-12, showed the former vice president with a small surge in Wisconsin since November when he trailed Trump 47% to 44%.