Grayson's Cheney endorsement: help or harm in GOP primary?

Trey Grayson's Senate campaign is rolling out the big guns, but does an endorsement from Dick Cheney really help in a Republican primary?

Grayson's campaign announced Cheney's backing Wednesday morning, with the former vice president calling the Kentucky Secretary of State a true conservative.

“I’m a lifelong conservative, and I can tell the real thing when I see it. I have looked at the records of both candidates in the race, and it is clear to me that Trey Grayson is right on the issues that matter – both on fiscal responsibility and on national security,” Cheney said.

Cheney also endorsed in the Texas governor's race, and it didn't seem to do Sen. Kay Bailey Hutchison (R-Texas) any good. As with Grayson, Cheney's endorsement in that race came down later in the race, when the endorsee looked to be in some serious trouble.

Grayson has plenty of ground to make up on Rand Paul, according to recent polling. And one has to wonder why, when there's such a premium on being the anti-establishment candidate these days -- that's really what Paul has working for him -- he's rolling out an endorsement from such an establishment figure.

It's hard to see Grayson making this move if he was tied with Paul or in the lead.