The should worry that Tea Partiers won’t turn out for Romney.
As bad as Obama is, if the GOP nominates McCain version 2.0 a significant percentage of Tea Pariters just won’t vote for him this time around.
They should be more worried that as his record is published the conservatives won’t turn out for him either. It’ll be amusing to see if he speaks up on Obama’s unilateral DREAM act that is modeled after what Perry instituted.