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..... “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 . . . state and not succeeded. And I think that the conservatives have to think through the right strategy if they hope to stop Romney....