Mitt Romney is getting tough – Romney-style.

The former governor of Massachusetts is taking on Newt Gingrich – finally, say supporters – after being eclipsed by the former House speaker in polls for the Republican presidential nomination. But Mr. Romney is largely delegating the attacks to others.

In an ad released Friday morning, the Romney campaign went after Mr. Gingrich for attacking fellow Republican Paul Ryan, a rising star in the party, over his plan last spring to reform Medicare. He had called the plan “right-wing social engineering.”