Newt needs to stay in for the simple fact that he’s the better candidate, more conservative, a better debater, and simply more experienced and capable than Santorum is.
Frankly, I don’t care how many primaries Santorum has won - if he were truly interested in the good of the country as a whole, he’d bow out and toss his delegates to Newt.
and why oh why do the Santorum folks think the Newt supporters would rally around Santorum?