Senate Minority Leader Mitch McConnell finally stepped out from behind the curtain on Tuesday to publicly endorse Kentucky Secretary of State Trey Grayson in the GOP primary to replace retiring Sen. Jim Bunning (R).

McConnell has been aiding Grayson behind the scenes since last year, but he had not taken a public role in the campaign until Tuesday.

McConnell’s endorsement of Grayson comes two weeks before his May 18 primary against Rand Paul, a first-time candidate with strong financial wherewithal, the backing of many tea party activists and the endorsements of Bunning and former Alaska Gov. Sarah Palin (R).

In a commercial being aired by the Grayson campaign, McConnell speaks directly to the camera. “I know Trey Grayson and trust him,” McConnell says in the ad. “We need Trey’s conservative leadership to help turn back the Obama agenda.”

The Grayson campaign released an internal poll suggesting the nomination fight is deadlocked, with each candidate pulling 40 percent of the vote.

A Public Policy Polling survey released a few hours later offered very different numbers; the PPP said it found that Paul, the son of Rep. Ron Paul (R-Texas), was favored by 46 percent of likely GOP voters versus 28 percent for Grayson.

The PPP survey, conducted May 1-2, sampled the opinions of 363 Republicans and had a 5-point margin of error.

On the Democratic side, the PPP found Lt. Gov. Daniel Mongiardo favored by 36 percent versus 27 percent for Attorney General Jack Conway.

That part of the poll sampled 459 likely Democratic primary voters and had a margin of error of 4.6 points.