A former House speaker considered a potential candidate for the Republican presidential nomination in 2008, Newt Gingrich, is sharpening his critique of the Bush administration over the its handling of Iraq and issues at home.

During speaking engagements Monday at the University of South Dakota, Mr. Gingrich faulted the White House for installing an American-run government in Iraq after Saddam Hussein was driven from power.

“It was an enormous mistake for us to try to occupy that country after June of 2003,” Mr. Gingrich told students and faculty, according to the Argus Leader of Sioux Falls, S.D. “We have to pull back, and we have to recognize it.”

Mr. Gingrich, who led the House from 1995 to 1999, also took a swipe at Mr. Bush’s decision not to seek congressional approval before implementing a wiretapping program aimed at uncovering communications involving possible Al Qaeda operatives.

“Where I fault the administration is, sometimes it would be so easy to just be simple and straight,okay? All they had to do is go to the American people and say, we want to make sure that if the National Security Agency picks up a foreign terrorist calling someone in the U.S., that they can listen to the call,” Mr. Gingrich said in a video clip posted on the South Dakota newspaper’s Web site. He said more than 90% of Americans would have quickly endorsed such a program.

The barbs from Mr. Gingrich, the architect of the “Contract with America,” come as he is in the midst of a speaking tour that is taking him to states that could be pivotal to the presidential primary contest in 2008. The former speaker is scheduled to be in New Hampshire today to address a health care-related meeting, as well as a local political fund-raising dinner, an aide to Mr. Gingrich, Rick Tyler, said.

Mr.Tyler said yesterday that Mr. Gingrich’s remarks Monday were consistent with his long-standing criticism of the handling of the aftermath of Iraq, including the creation of the Coalition Provision Authority. In his South Dakota comments, he railed against the installation of “an American proconsul,” Jerry Bremer, to run postwar Iraq.

Mr. Gingrich “has been saying since 2003 that Bremer was a mistake. The CPA was a mistake.We are currently in the mode of occupation not liberation,” Mr. Tyler said.

A political analyst with the American Enterprise Institute, Norman Ornstein, said he does not believe that Mr. Gingrich is calibrating his message on Iraq with one eye on Mr. Bush’s sinking poll numbers. The former speaker “is expressing the frustration over the failures early on which have led to this pretty difficult situation. This is something he genuinely believes,” the analyst said.”He’s not just doing it because the president is weak.”

As some top contenders for the Republican nomination in 2008, such as Senator McCain of Arizona, tack to the right to appeal to the conservatives who form the party’s base, Mr. Gingrich appears to be making an active effort to court moderates.

During one of his appearances Monday, Mr. Gingrich went out of his way to emphasize the importance of the ideological center to the Republican Party.

“You can’t be on the two wings and win in America,” he said, according to a video posted on the University of South Dakota Web site. “I would argue the Republican Party ought to be a center-right coalition.”

Mr. Ornstein said Mr. Gingrich’s comments suggest that he does not believe that Republicans can win the 2008 race with the same strategy that carried the day in 2000 and 2004. “He believes the dynamic that got George Bush elected and re-elected, a divider-not-a-uniter strategy of appealing only to the base, is a non-starter now,” the analyst said.

Mr. Ornstein said one challenge to Mr. Gingrich’s possible candidacy is whether he can win the trust of moderates who viewed him as a polarizing figure during his high-profile showdowns with Mr. Clinton in the 1990s. “That’s a question we don’t know the answer to,” Mr. Ornstein said.

The former speaker is expected to continue to train some fire on the White House. Mr. Gingrich and the president of the Heritage Foundation, Edward Feulner,have penned an op-ed piece attacking the administration for failing to transform the federal bureaucracy. The article will appear this week in a New Hampshire newspaper, the Manchester Union-Leader, Mr.Tyler said.