President-elect Donald Trump and his Democratic opponent Hillary Clinton will face off in the Pennsylvania primary on Tuesday, but there are many unanswered questions about who they will face.
In a sign of the challenges ahead, the two candidates are struggling to stay relevant, with Trump losing to Democratic rival Joe Biden in Pennsylvania in 1992.
Polls have tightened considerably in Pennsylvania, but it’s still too early to know what will happen.
Trump is in the middle of an overhaul of the Republican Party.
He has announced he is running as a Republican for president, but he is also running for re-election.
He wants to replace President Barack Obama with a Republican, and he has vowed to make big changes to the party and the Republican-led Congress.
Biden, who has served as vice president, was elected to the Senate in 2006.
He is the only Democrat to hold the seat in the state.