By John Whitesides

SIOUX CITY, Iowa (Reuters) - Despite months of campaign-trail neglect, Iowa could still be the unlikely launching pad for a Mitt Romney run to the Republican presidential nomination in 2012.

Romney led one recent poll in the state that holds the first nominating contest of the race, even though he has rarely visited Iowa since a crushing second-place finish here put his 2008 campaign on a path to failure.

With conservative rivals Michele Bachmann and Rick Perry fading and Republicans desperately seeking a candidate who can beat President Barack Obama, Romney is suddenly in a strong position in Iowa and facing questions about whether he will intensify his efforts here.

The rewards could be powerful. A win or a strong second on January 3 in Iowa, combined with a victory in the next contest in New Hampshire, where he holds a big lead in polls, would almost certainly set Romney toward the nomination.

"I think there definitely is an opening for Romney in Iowa. The time and money and effort he invested four years ago have not been forgotten," said Tim Albrecht, a Romney aide in Iowa in 2008 who is now spokesman for Iowa Governor Terry Branstad.

"If he can deliver a one-two knockout punch with Iowa and New Hampshire, it's over," he said.

The former Massachusetts governor made three campaign stops in western Iowa on Thursday -- just his third visit to the state this year -- and was immediately hit with a voter's question about when and how often he would be back.

"I will be here again and again," he said, echoing the same promise he made on his last visit in August. "I want to win in Iowa."

But for Romney, the bitter memories of 2008 are hard to overcome. He spent millions of dollars and built a large organization in Iowa that led him to a straw poll victory, but social conservatives coalesced behind former Arkansas Governor Mike Huckabee to give him the win.

After Iowa, Romney lost in New Hampshire to eventual nominee John McCain and his once-promising campaign quickly ran out of steam.

This time around, Romney skipped the Iowa straw poll in August and has largely ignored Iowa to focus on New Hampshire. If he changed his approach and put more effort into Iowa, only to lose again, it could be a devastating setback to the front-runner.

'A HURDLE'

Romney still has problems with the social conservatives who play a dominant role in the state party. They distrust him for his past support for abortion rights and for an individual mandate in the Massachusetts healthcare overhaul.

"That will be a hurdle for him to overcome," said Chuck Soderberg, a state representative from Le Mars who supported Romney in 2008 but is uncommitted this time. "I think he can win here, he has a strong base from four years ago."

The Real Clear Politics average of Iowa polls shows conservative businessman Herman Cain leading Romney by four percentage points, 26 percent to 22 percent, although an NBC News/Marist College poll earlier in the month had Romney up by six points on Cain.

But Cain, Perry, Bachmann, former U.S. Senator Rick Santorum and U.S. Representative Ron Paul have split the support of conservatives in Iowa this year, leaving Romney a possible path to victory.

"His support is very solid, it hasn't gone up and down like the others. If the conservatives split up the vote he could win with 23 to 25 percent," former state party chairman Steve Roberts said.

Several Iowa activists said the state's Republican electorate had changed since 2008, with more interest in beating Obama and fixing the economy.

"I think it's a mistake for him to continuously look at Iowa through the lens of the 2008 campaign," said Craig Robinson, a former state party political director who now runs the Iowa Republican website.

"The things that are motivating people are different than four years ago," he said. "Romney's advantage is that the economy is bad and people look at him as a very formidable candidate when it comes to economic issues."

Romney has four paid staff and a consultant working in Iowa to organize support for the contest, but his campaign has been careful to keep expectations in Iowa low. Robinson said the expectations game would only get Romney so far.

"Whether or not he's here, he has expectations to do well as the national front-runner," Robinson said. "So it would be wise to embrace Iowa in some capacity and not just blow it off."

(Editing by Alistair Bell and Xavier Briand)