By Richard S. Dunham and Carla Marinucci

Hearst Washington Bureau

MANCHESTER, N.H. — During the GOP debate here Saturday night, Rick Perry declared that as president, he would send American troops back into Iraq.

Calling the withdrawal of American troops a huge error, the Texas governor said: “We are going to see Iran, in my opinion, move in at literally the speed of light.”

Perry also said the withdrawal was because President Barack Obama was seeking to appease his liberal voting base.

The governor’s statement failed to provoke much excitement on the debate stage. Asked whether he agreed with Perry, Newt Gingrich simply said, “Well, no. … “

Meanwhile, Perry, the former House speaker and the other three presidential hopefuls trying to emerge as the alternative to front-runner Mitt Romney targeted each other during the debate at St. Anselm College.

For his part, the former Massachusetts governor grinned at the theatrics while aiming his political barbs at Obama.

With just three days left before New Hampshire’s primary, Romney took the opportunity to repeatedly skewer the Democratic incumbent’s economic record and foreign policy.

“His policies have made the recession deeper, and his policies have made the recovery more tepid,” Romney said.

The ABC News debate was the first of two nationally televised encounters in 12 hours. The candidates will reconvene 15 miles north for a debate at 8 a.m. CST today in Concord.

The back-to-back weekend debates are the last chance to slow Romney’s momentum before New Hampshire voters cast their ballots.

Polls show him running more than 20 percentage points ahead of his opponents in New Hampshire and vaulting into the lead in the next state to hold a primary, South Carolina.

University of Virginia government Professor Larry Sabato called the debate “a classic case of a front-runner winning by hiding in plain sight.”

As Romney watched, the other candidates repeatedly ripped into each other.

Lake Jackson Rep. Ron Paul, running second in recent New Hampshire polls, was at the center of the conflict during the debate also sponsored by WMUR TV and Yahoo! News.

He denounced Gingrich as a “chicken hawk” who avoided military service during the Vietnam War and called former Pennsylvania Sen. Rick Santorum “corrupt” and “a big spender.”

Both of Paul’s targets reacted furiously, with Santorum saying Paul had made “a ridiculous charge” and was “not telling the truth.”

“Well, Dr. Paul has a long history of saying things that are inaccurate and false,” Gingrich chimed in. “The fact is, I never asked for deferment. I was married with a child. … And I personally resent the kind of comments and aspersions he routinely makes without accurate information and then just slurs people with.”

“When I was drafted,” Paul shot back, “I was married and had two kids, and I went.”

Perry, placed on the far-right podium after finishing fifth in last week’s Iowa caucuses, used his rare questions to demonize his opponents — with the exception of former Utah Gov. Jon Huntsman — as corrupt insiders.

“It doesn’t make any difference whether you’re an insider from Washington, D.C., or you’re an insider from Wall Street,” Perry said. Americans, he continued, are looking for “an outsider that is not corrupted by the process.”

Perry also blasted fellow Texan Paul for seeking federal projects for the Lone Star State while speaking out against federal spending.

“In Texas, we call that hypocrisy,” Perry said.

“I call that being a constitutionalist,” Paul responded.

Criticism of Romney was rare during the 100-minute debate.

Huntsman noted that Romney’s job-creation record as Massachusetts governor was 47th in the nation, while Utah led the nation.