Biden still has a path to victory without Pennsylvania, but it’s a narrower one. His clearest roadmap relies on flipping several Rust Belt states where Trump edged out Clinton: Pennsylvania, Michigan and Wisconsin. Biden’s leads in the latter two appear more solid, but in the Keystone State he’s only within the polling margin of error, and a number of recent surveys by more conservative entities show an even tighter race. (The RealClearPolitics poll average has him up by 3.8 percentage points.)

Several shifting factors that could influence the outcome are still very much in play. Pennsylvania election officials are still scrambling to finalize plans for their first year of vastly expanded mail-in voting. The U.S. Supreme Court on Wednesday denied a request by the Republican Party to fast-track a decision on whether to overturn a ruling by the state’s Supreme Court to extend the mail-in deadline.

It’s also unclear how voters will respond to the police killing of a knife-wielding black man in Philadelphia earlier this week. Violent protests and looting broke out two days ago, with dozens of police officers injured and curfews declared in an attempt to quell the unrest.

Team Trump isn’t making it easy for the Scranton native to put Pennsylvania in his rearview mirror.