WASHINGTON (AP) — Mitt Romney says his business background makes him a better presidential candidate than Newt Gingrich, who has spent decades in Washington. But the argument is not moving Republicans his way, underscoring Romney's challenge in finding a way to stem Gingrich's rise three weeks before the Iowa caucus, a new Associated Press-GfK poll finds.

Republicans are evenly divided on whether a Washington insider or outsider is best-suited to be president. That's a problem for Romney, who cites his private-sector experience as the biggest difference between the two front-runners for the GOP nomination.

The poll also found a significant drop in satisfaction with the overall field of Republicans vying to challenge President Barack Obama next year. In October, 66 percent of Republican adults were satisfied with the field, and 29 percent unsatisfied. Now, 56 percent are satisfied and 40 percent unsatisfied.

Except for four years as Massachusetts governor, Romney, 64, has spent his career in business and management. He ran unsuccessfully for the Senate in 1994 and for president in 2008.

Gingrich, 68, spent 20 years in the U.S. House, including four as speaker. Since 1998, he has had a lucrative, Washington-based career as a consultant, speaker and author.

Both men have earned millions of dollars over the years.

The AP-GfK nationwide poll of Republicans found Gingrich with an edge over Romney as the candidate they'd like to see win the nomination. However, it falls just within the poll's margin of error of plus or minus 6 percentage points.

Voter preferences in early voting states such as Iowa, New Hampshire and South Carolina do not necessarily match those in national polls. The Iowa caucus is Jan. 3. The New Hampshire primary is one week later.

For months, Romney has hovered at or near the top of Republican polls, while various rivals have risen and fallen. Gingrich's rise is at least as dramatic as the recent plummets of businessman Herman Cain and Texas Gov. Rick Perry.

An October AP-GfK poll of Republicans found Gingrich well behind the leading candidates, with 7 percent. Romney had 30 percent. The new poll finds Gingrich preferred by 33 percent of Republicans and Romney by 27 percent. All other candidates are in single digits.

Jonathan Luers, a software engineer from Chicago, is among those Republicans less than thrilled about the field.

"I guess I'm a little disappointed that it's been so fluid," said Luers, 52. "I was kind of hoping there would've been a more clear choice, without the quick knockdowns and everything." He said he's leaning toward Gingrich.

Romney has built his campaign largely on the argument that his business background makes him better suited for the presidency than anyone else, especially in terms of creating jobs. In a debate Saturday in Iowa, Romney struggled at first to name areas in which he and Gingrich disagree.

After citing Gingrich's support for a mining colony on the moon and changes to child labor laws, Romney said: "The real difference, I believe, is our backgrounds. I spent my life in the private sector. I understand how the economy works."

Among Republicans who say they prefer a non-Washington candidate, Romney has a modest edge over Gingrich. Gingrich has a larger advantage among those who say they prefer Washington experience in a nominee.

Among all people surveyed in the AP-GfK poll, including Democrats and independents, Romney fares better than Gingrich in head-to-head matchups with Obama. Obama and Romney are statistically even. But Obama leads Gingrich 51 percent to 42 percent.

That may give Romney some ammunition with Republicans whose top priority is ousting Obama. Otherwise, Republicans appear to see Romney and Gingrich as similar in many important ways. The two men polled about evenly on the questions of who would be a strong leader, has the right experience, understands ordinary people's problems and can bring needed change.

Romney holds a clear edge on who is most likable. Gingrich leads on the question of who "has firm policy positions." Romney is often asked about his changed positions on abortion, gay rights, gun control and immigration. Gingrich, however, also has shifted views on some key issues over the years.

The poll found sharp drops in popularity for Perry and Cain over the past two months. Cain has suspended his campaign.

Dmitry Kan, a Republican who owns an advertising firm in Acton, Mass., is not enthusiastic about the field.

"There is not much choice," he said. "It looks like it's going to be either Romney or Gingrich."

Kan, who is 24 and emigrated from the former Soviet Union in 1992, said he is leaning toward Gingrich but might change his mind. He said he respects Romney's business background, but "seeing how it works these days, I think Gingrich's ability of political prowess might work better."

Kan said Gingrich "did some difficult stuff back in the 1990s, back in the Clinton administration. Hopefully he will be able to somehow break through the gridlock."

Catherine Sebree, 41, a homemaker from The Woodlands, Texas, likes Romney.

"I appreciate the values that he stands for," she said. "I believe that he is the person that will put family first and will help to strengthen our nation and hopefully help out with the budget deficit."

Sebree embraces Romney's non-Washington background. "I think that the people that are experienced in Washington have screwed up enough that it's time to try some different methods," she said.

The Associated Press-GfK Poll was conducted Dec. 8-12 by GfK Roper Public Affairs and Corporate Communications. It involved landline and cellphone interviews with 1,000 adults nationwide and has a margin of sampling error of plus or minus 4 percentage points.

The poll included interviews with 460 Republicans and Republican-leaning independents. The margin of error for these results is plus or minus 6 percentage points.