With Mitt Romney's decisive wins in three primaries Tuesday, and his mounting lead in delegates, it's only a matter of time before he sews up the GOP presidential nomination. But how much time will that be? Party leaders are urging Republicans to rally around Romney and stop the damaging primary fights. But Rick Santorum is pressing on, holding out for the April 24 primary in Pennsylvania, his home state. That's a risky gamble for both Santorum and the GOP. "Santorum runs the risk of either embarrassment, if he loses Pennsylvania, or becoming seen within his party as a spoiler if he stays in the race indefinitely and continues to attack Romney," the Washington Post reported.