How Big is Gregg's Endorsement?

Judd Gregg's endorsement of Mitt Romney may be a coup, but do endorsements really ever make that big a difference?  Anyone who believes they guarantee a win need only look to Gov. Engler's 2000 support of George W. Bush in Michigan (or for that matter, Gregg's support of Bush in 2000). 

As First Read reports:

GOP strategist Mike Murphy, who had a business relationship with Romney until early last year and worked in 2000 for McCain -- who won the state -- was once unimpressed with Gregg’s backing. Gregg had supported Bush eight years ago, but Murphy told the New York Times that the help of Gregg’s team was less of a boon and more hype, saying, “They can't even deliver a pizza.”