MANCHESTER, New Hampshire (AP) ― The once-bursting 2012 Republican presidential field is narrowing to a two-man race, and GOP voters have one month before casting the first votes to winnow it to one. Barring a dramatic new turn, their chief options will be the steady but often bland demeanor of Mitt Romney and the idea-a-minute bombast of Newt Gingrich.

Herman Cain’s suspension of his campaign Saturday, and Texas Gov. Rick Perry’s continued struggles to regain traction, have focused the party’s attention on Romney, the former Massachusetts governor, and Gingrich, the former House speaker. They offer striking contrasts in personality, government experience and campaign organization.

Romney has maintained a political infrastructure since his 2008 presidential bid, especially in New Hampshire. Gingrich, whose campaign nearly collapsed several months ago, is relying much more heavily on his televised debate performances and the good will he built up with conservatives as a congressional leader in the 1980s and 1990s.

Gingrich’s and Romney’s political philosophies and differences are a bit harder to tease out. Both men have changed their positions on issues such as climate change. And Gingrich, in particular, is known to veer into unusual territories, such as child labor practices.

Cain’s announcement in Atlanta offered a possible opening for Romney or Gingrich to make a dramatic move in hopes of seizing momentum for the sprint to the Jan. 3 Iowa caucus. Neither man did. They appear willing to play things carefully and low-key for now.

At a town hall meeting in New York sponsored by tea party supporters, Gingrich declined to characterize the race as a direct contest between himself and Romney. Any of the remaining GOP contenders could stage a comeback before the Iowa caucuses, he said. “I’m not going to say that any of my friends can’t suddenly surprise us,” Gingrich said.

But once high-flying contenders such as Perry and Rep. Michele Bachmann of Minnesota have not managed to bounce back so far, despite weeks of trying.

Romney seemed as eager as Gingrich to avoid casting the contest as anywhere close to decided. He repeatedly turned aside reporters’ invitations to light into Gingrich, offering only gentle critiques. As usual, he aimed much sharper remarks at President Barack Obama.

“I don’t think people have really settled down, in a final way, to decide who they’re going to support in the nomination process,” Romney told reporters in Manchester, where he held a rally and knocked on a few doors. “I hope they give us a good, careful look.”

That was about as much emotion and daring as he showed all day. With the second-tier candidates ramping up their criticisms of Gingrich, Romney stuck to his steady-as-she-goes campaign style of criticizing Obama’s economic record, and saying little else.

Cain’s once-prospering campaign was undone by allegations of sexual wrongdoing. Gingrich has been the most obvious beneficiary of Cain’s precipitous slide. But Perry, Bachmann and possibly others are likely to make a play for Cain’s anti-establishment tea party backing. Time is running short for them to establish themselves as the top alternative to Romney, who has long been viewed with suspicion by many conservatives.

Cain said he would offer an endorsement. His former rivals were quick to issue statements on Saturday praising his conservative ideals and grassroots appeal.

Romney seemed loath on Saturday to criticize Gingrich or to stir the political waters. Reporters asked why his background makes him more qualified than Gingrich. “Speaker Gingrich has been a legislator and has worked in government affairs, and he can describe his own background,” Romney replied.

Why are his positions better than Gingrich’s on issues such as immigration, Romney was asked. “We have very similar views on a whole host of issues,” he said. “There are some places, I’m sure, where there are differences.” The biggest difference, he said, is “our life experience.”

Asked if he fears that Gingrich will draw more tea party support, Romney said tea party activists “want someone who comes from outside Washington,” someone who has spent his life “in the private sector, who has learned the experiences of the American economy.”

“Speaker Gingrich is a fine person,” Romney said, “but he spent his life in Washington, the last 40 years. That doesn’t exactly line up with the tea party.”

He also said he differed with Gingrich on child labor laws. Gingrich recently suggested that children as young as nine should work as assistant school janitors, to earn money and learn work ethics.

Romney noted that Gingrich would end taxes on dividends and capital gains for everyone, whereas Romney would keep them in place for the wealthiest Americans.

Romney’s generally mild reproofs contrast with the hits Gingrich is taking from rivals such as Rep. Ron Paul of Texas. Paul’s campaign is airing a video accusing Gingrich of “serial hypocrisy.” It shows Gingrich in a TV commercial with former Speaker Nancy Pelosi, D-Calif., talking about the dangers of climate change.

Gingrich has called the Pelosi spot a stupid mistake on his part.

Romney’s campaign had hundreds of volunteers knocking on doors and making phone calls Saturday, pushing a slogan that presidential hopefuls must “earn it.”

Romney has a vacation home in New Hampshire, where he is well known. His campaign structure there isn’t perfect, however.

Aides sent reporters to 827 Chestnut Street in Manchester, where Romney would start some door-knocking of his own. But there was no one home at 827, or the next house he tried, or the three after that. In nearly an hour of door-knocking, Romney met only a handful of voters, and all of them already seemed in his corner.

Asked at the day’s end why he was being so gentle with Gingrich, Romney replied: “I think the right course for me is to continue talking about my vision for the country, my experience, and how I’d lead the nation. And Speaker Gingrich will get the chance to do the same thing.”