A bitter and often personal debate behind them, Republicans Rick Santorum and Mitt Romney are shoring up their campaigns in different ways ahead of a series of crucial presidential primaries.

Romney is paying more attention to Michigan, his birthplace and
the site of an unexpectedly tight race with Santorum, by attending a tea party rally Thursday night in an effort to get more conservative support.

Santorum is focusing for the moment on raising money for his
cash-strapped operation. He is hoping for an upset in Michigan,
which would cap a rebound that began two weeks ago with victories
in three states.

The 20th debate of the primary season offered the GOP hopefuls
their final face-to-face outing before contests over the next 12
days that may well winnow the field.