The independent expenditure arm of the National Republican Senatorial Committee is launching its first TV ad of the cycle in Kentucky, where Republican Rand Paul and Democrat Jack Conway are battling for an open seat.

The ad ties Conway to President Barack Obama and Speaker Nancy Pelosi (D-Calif.), and attacks his support for the health care reform bill.

“Whose horse is Jack Conway riding?” the ad’s announcer asks. “Big government health care. Big cuts to Medicare. Jack Conway took their side. Jack Conway, he’s not riding Kentucky’s horse.”

The fact that the NRSC’s first ad of the cycle went up in Kentucky will burnish Democrats’ argument that the GOP is concerned about Paul’s candidacy. Also, in what appears to be a strong environment for Republicans to pick up a number of Democratic-held seats, the committee is playing defense early to help save the seat being vacated by Republican Sen. Jim Bunning.

But Republicans point to recent polling that showed Paul leading by significant margins. Public Policy Polling, a Democratic firm based in North Carolina, released a poll Tuesday that showed Paul ahead 49 percent to 42 percent. By launching the ad now, the committee hopes to help Paul increase that lead heading into October.

“We want to define him early and take this race off their radar screens,” said a Republican source familiar with the committee’s thinking. “We’ll do that by wrapping the Obama agenda right around Jack Conway.”

While this is NRSC’s first ad, the Democratic Senatorial Campaign Committee’s IE has so far paid for ads in Missouri, Pennsylvania and Colorado. Democrats are trying to hold the Pennsylvania and Colorado seats, and are looking to pick up an open seat in Missouri.

Conway went up with an ad of his own on Tuesday, taking aim at Paul for being soft on crime. The state Attorney General’s new ad, his second of the general election, focuses on a comment Paul made on Kentucky Education Television’s “Kentucky Tonight” show last fall, in which he indicated that nonviolent crimes should not be against the law.

Conway’s camp pounced on the comment as a way to paint Paul as being out of touch, especially in light of statements he has made questioning the Civil Rights Act of 1964 and a more recent comment about drugs not being a pressing issue in the state.

Conway’s ad features several Kentucky sheriffs discussing Paul’s comment on nonviolent crimes.

“He just doesn’t get it,” says one.

“We need a Senator that’s going to treat criminals like criminals,” says another.

The new ad will air in the state’s four main media markets in Lexington, Louisville, Evansville and Peducah. It is scheduled to be on the air for at least two weeks.