When President Donald Trump nominates a Supreme Court justice , Senate Democrats and Republicans will immediately face intense political pressure, with liberals demanding that Democrats block the choice and the new president urging Majority Leader Mitch McConnell to blow up longstanding rules to secure confirmation. Federal appeals court judges William Pryor, Neil Gorsuch and Thomas Hardiman are front-runners to fill the seat of the late Justice Antonin Scalia, according to a person familiar with the process who was not authorized to speak publicly about internal decisions and discussed the search on condition of anonymity.