The hope is that delegates will go with Santorum as the more conservative option over front-runner Romney. But there's a hitch: Newt Gingrich is refusing to quit the race.

It's a long-shot gamble for a candidate who began as long shot and badly trails Romney in delegates leading to the August convention in Tampa, Fla., where Republicans will pick a challenger to President Barack Obama.

Adding to Santorum's money and organizational challenges is the fact that Gingrich is splitting the conservative vote and is dismissing pressure by Santorum to drop out after losing this past week in Alabama and Mississippi.