N.H.'s Gregg For Romney

Do endorsements matter?

Mitt Romney is about to pick up a key vote of support that could help answer that question. Later today, Romney will receive the endorsement of New Hampshire Sen. Judd Gregg in Concord, according to the campaign.

New Hampshire is quickly becoming the key battleground for the Republican candidates. With Romney far out in front in Iowa, the battle in the Granite State is shaping up to be the first real test for all of the leading contenders.

Romney has been pouring money into the state, and clearly hopes that Gregg's support will translate into votes on primary day (whenever that will be.)

But his rivals--particularly former New York mayor Rudy Giuliani and Arizona Sen. John McCain--are not giving the state up without a fight.

Giuliani plans to spend almost the entire week in New Hampshire and McCain's advisers have said they believe the state is the one place their candidate might be able to revive his flagging candidacy.

Gregg will join Romney at a rally at the steps of the state library this afternoon before Romney officially files as a candidate in the New Hampshire primary.

--Michael D. Shear