Party's chances are "almost non-existant" without move in immigration, he says.
Senate Republicans will have to work hard to retain their majority.
“I'm not done,” he said in a message from teh group.
Hillary Clinton remains the odds-on favorite to win the Democratic presidential nomination.
Bush leads New Jersey Gov. Chris Christie by 10 points in a CNN/ORC poll.
Texas governor tells CNN that Americans are looking for "exactly what we've done."
Mike Lillis 12/26/14 02:10 PM EST
Some House Republicans will be in serious danger at the next elections.
"I don't want to do it unless we can win this thing," he told the AP.
Alexander Bolton 12/26/14 05:53 AM EST
Allies say rivals such as Christie and Walker are more likely to be affected.
Nineteen percent aren't sure who they want to run for the nomination.