No more Mr. Nice Guy (even if he was never all that nice). Former House speaker Newt Gingrich is out with his first ad attacking former Massachusetts governor Mitt Romney:

The spot, “Timid vs. Bold,” will start airing in New Hampshire and South Carolina within 48 hours. The Gingrich campaign calls the ad buy “significant.”

“Romney’s economic plan? Timid,” the narrator says. “Parts of it virtually identical to Obama’s failed policy. Timid won’t create jobs. And timid certainly won’t defeat Barack Obama.” The ad also praises Gingrich’s jobs plan as “a powerful plan for growing our economy and creating jobs.”

It’s not nearly as harsh as some of the attacks on Gingrich from the pro-Romney super PAC Restore Our Future. But Gingrich supporters have their own super PAC, Winning Our Future, which will go on the air in the coming days.

After pledging to run a positive campaign, Gingrich pledged last night to draw a “direct and sharp contrast” with Romney.

Gingrich has already taken a tougher tone on the campaign trail since placing fourth in Tuesday’s Iowa caucuses, saying in New Hampshire that “Romney has a very limited appeal in a conservative party.” He ran a full-page ad in the New Hampshire Union-Leader calling Romney the “Timid Massachusetts Moderate.”