This is a very big deal for the Romney campaign.  As the Manchester Union Leader reports, Senator Gregg had previously indicated he would not be endorsing until after the primary.  Senator Gregg's endorsement is the most sought-after in the Granite State, and it adds to the sense of momentum that Romney has built there.  Romney is also the candidate least likely to take anything for granted, especially in a state with a record of surprising front runners.   

The obviousness of the two-candidate race within the GOP just got even clearer.  Expect more and more senior GOP leaders to realize the time is now for choosing between Giuliani and Romney and to make their announcements accordingly.