The National Federation of Independent Business, which fought President Obama's health care law all the way to the U.S. Supreme Court, has launched an ad campaign in Arkansas, site of a closely-watched 2014 Senate race.

The ad, which features a small business owner discussing the burdens imposed by the law, is not so subtly aimed at Sen. Mark Pryor, the state's Democratic senator who is at risk of losing his seat next year in large part due to his vote for Obamacare.

The NFIB, through its activist arm, the Voice of Free Enterprise, said it was putting $500,000 into the ad, which ends by encouraging Arkansans to call Pryor.

I've embedded a 60-second version of the ad. There is also a 30-second version.