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That's the question I asked ABC News contributor Matt Dowd ahead of tonight's primary. Mitt Romney has been bouncing up and down in the polls of his home state, and is now neck and neck with Rick Santorum.

"If Rick Santorum wins tonight it's the equivalent of a 9.0 on a Richter scale. I mean it is going to shake Washington, it's going to shake Republican establishment it's just going to shake things to their very core," Dowd told me. "And I think what you're going to see are the conversations that have been going on behind quiet doors saying we need another candidate in this race."

But how can another Republican jump in?  After Super Tuesday, the filing deadlines will be open in only seven states.  Even if a candidate can manage to get on the ballot - and win every one of those states - he or she will still have fewer than a third of the delegates needed for the nomination.

Dowd says Republicans could recruit another candidate to shake things up and "demonstrate that these guys are not the guys that are most electable."

"They may not be able to win the number of delegates, but if nobody gets the majority of the delegates going into the convention, if somebody comes out from behind the scene and shows up tomorrow or in the next week or two they could actually show that they could win this," Dowd said on "GMA."

Take a look at my interview here: