Even after Mitt Romney’s hat trick last night, Rick Santorum still has hope that he can stop the former Massachusetts governor from securing the nomination. It’s just halftime, he says, and he’s counting on Pennsylvanians to “charge out of the locker room” for a strong second half. The former Pennsylvania senator has repeatedly predicted a win in his home state, where both he and Mitt Romney campaign today:

Speaking on familiar turf, the former two-term senator from the Keystone State urged supporters to dismiss attacks from his opponents ahead of Pennsylvania’s primary later in April.

“You know me. You know how hard I work,” Santorum said. “They’ll say all the things, that I’m someone who doesn’t stand up for what I believe in. You know me.”

In recent days, Santorum has predicted he will win his home state’s contest, which has 72 delegates at stake. He also expects to push on through May, a month that holds contests in states that are more conservative. …

In an interview on Monday on CNN’s “Piers Morgan Tonight,” Santorum acknowledged that “April would be a very tough month for us,” but he intends to compete through May and onto the convention.

“May is rich with delegates and are strong states for us — states like Texas and Arkansas and Kentucky and Indiana, West Virginia, North Carolina. Those are the states that we know we can get this back, right back to where it is right now, which is a lot closer than what Mitt Romney and the pundits are spinning,” he said.

No doubt Mitt Romney will repeat in Pennsylvania the strategy that worked so well for him against Gingrich in Florida and against Santorum in Ohio, Michigan, Illinois and Wisconsin. He’ll purchase expensive advertising, utilize compelling robocalls and crisscross the state himself. He has even more incentive than usual to deploy a deal-sealing barrage of negativity against Santorum. If he can sneak to victory in Pennsylvania, he’ll have made a very strong case for himself against Santorum.

Santorum is counting on his home-state advantage to help him withstand the assault. In the latest Quinnipiac University poll in Pennsylvania, Santorum leads Romney by six points. If that begins to change, though, and a loss in Pennsylvania for Santorum looks likely, Romney’s last challenger might not make it to May.