DES MOINES, Iowa - Former U.S. House Speaker Newt Gingrich said Monday he's seriously considering seeking the Republican presidential nomination and will announce his decision early next year.

Gingrich, 67, told The Associated Press that he would focus on helping Republican candidates through the midterm elections in November, then decide in February or March whether to seek the GOP nomination.

"I've never been this serious," Gingrich said.

"It's fair to say that by February the groundwork will have been laid to consider seriously whether or not to run," he said.

Gingrich, in Des Moines for a fundraiser and workshop for local Republican candidates, predicted President Barack Obama would be a one-term president. Obama's poll numbers have dropped below 50 percent, and Gingrich predicted they would continue to fall, making him vulnerable in 2012.

Unlike President Bill Clinton, who rebounded from first-term problems by pushing for welfare reform and budget balancing changes that pleased moderate voters, Gingrich argued that Obama shows no inclination to move toward the center.

"He's not like Bill Clinton," Gingrich said. "Bill Clinton was an Arkansas, Southern Baptist, sort of understood middle American. While he had some Yale overtones being liberal, the truth is Bill Clinton was quite happy to move to the right."

Gingrich has been mentioned as a possible 2012 presidential candidate along with other Republicans, including former vice presidential nominee Sarah Palin, Minnesota Gov. Tim Pawlenty and former Massachusetts Gov. Mitt Romney.

Gingrich had a long congressional career and was House speaker from 1995 to 1999. He was given much of the credit for the Republican takeover of the House in 1994. But he abruptly resigned from Congress in 1998 after his party fared poorly in midterm elections. He also was reprimanded by the House ethics panel for using tax-exempt funding to advance his political goals.

The former speaker, who championed a family values agenda, spearheaded efforts to impeach Clinton for perjury over his affair with White House intern Monica Lewinsky. Gingrich later admitted having an extramarital affair of his own in 1998 with a former congressional aide, Callista Bisek. He married Bisek after divorcing his second wife, Marianne.

After leaving Congress, Gingrich created American Solutions for Winning the Future, a tax-exempt organization that promotes conservative causes. He acknowledged considering a White House run in 2007 and said he also thought about a run against Clinton before deciding it wasn't possible.

"You couldn't be the first Republican speaker in a generation and engage in a contest with Bill Clinton for setting the direction of the country and run for president," said Gingrich. "It wasn't physically doable."

Gingrich said he would to return several time this year to Iowa, where precinct caucuses lead off the presidential nominating process. He said he planned to lay the groundwork for a campaign by working hard for Republicans in the midterm elections.

Gingrich is known for his frequently harsh rhetoric, and he didn't hold back in speaking about Obama.

"I think he will replace Jimmy Carter as the worst president of modern times," said Gingrich.

Thanks to Obama's performance, Gingrich said he expected that whoever wins the Republican nomination would win the White House.

"He is a disaster," Gingrich said of Obama. "His principles are fundamentally wrong. The people he appoints are more radical than he is and less competent."

Despite his fiery personality, Gingrich said he wasn't worried that his comments would turn off moderate voters. At a time when the economy remains fragile, Americans want results and aren't worried about personality, he said.

"I think likable is a word you have to think about a lot," said Gingrich. "If people believe their country is in trouble, they want a captain of the lifeboat, they don't want a fraternity brother."