Presidential hopeful Newt Gingrich says Rick Santorum’s double-digit loss in the Illinois primary shows he is not the conservative alternative to Mitt Romney — and he can’t defeat President Barack Obama. The former House speaker also told Fox News’ Sean Hannity Tuesday night that he is staying in the race because he is that alternative — and he can win in November. “Governor Romney had a pretty good day — I think he took a step towards clearly proving he was the front-runner. Senator Santorum didn’t have a particularly good day,” Gingrich said. “This is the third time now he has tried an industrial Midwestern union state and not succeeded. And I think that the conservatives have to think through the right strategy if they hope to stop Romney.