Rep. Bill Cassidy really doesn't like Obamacare. Also, he's a doctor.

That, in short, is the message of the first TV ad of the Republican's campaign for U.S. Senate in Louisiana. The congressman dons a white lab coat and scrubs for a 30-second commercial in which he lays out his opposition to the law from the perspective of a physician.

"Most in Congress who voted for Obamacare never read the bill," Cassidy says. "It affects your job, your pocketbook, your life. And they didn't read it. I read the bill. It was clear there would be canceled plans, expensive premiums, no guarantee you could keep your doctor. I voted no."

The Cassidy ad suggests two things about his strategy: One, his campaign thinks the health-care law, although it has recently been overshadowed by other issues in the national debate, will continue to resonate with voters. Two, his pitch is improved and less politicized if he makes it from the point of view of a doctor rather than a congressman.

Cassidy concludes by calling for an Obamacare replacement that "gives the power to you."

He is the Republican front-runner against Sen. Mary Landrieu (D), who voted for the health-care law. Landrieu's first TV ad, released in December, trumpeted her proposals to fix the plan at a time when problems with its rollout were receiving widespread attention.