DES MOINES, Iowa – He could easily win the Iowa precinct caucuses Tuesday, which kick off the voting for the 2012 Republican presidential nomination.

Yet Ron Paul is largely getting a free pass from his rivals, the only top-tier candidate who's escaping the torrent of high-profile attack ads flooding the state's airwaves.

Why? Because none of his competitors sees the Texas congressman as a serious long-term rival for the nomination. One, Mitt Romney, sees a Paul win in Iowa as the next best thing to a Romney win, something that would deny an Iowa launching pad for a more serious long-term challenger such as Newt Gingrich or Rick Perry.

"Ron Paul is actually helping Romney," said Craig Robinson, the editor of the Iowa Republican website and former political director of the Iowa Republican Party.

Gingrich, the former speaker of the House, did criticize Paul in an interview this week with CNN, saying he wouldn't vote for Paul if he were the party's nominee. And Michele Bachmann hammered Paul's isolationist approach to foreign policy during an Iowa debate Dec. 15.

But neither is backing up those charges with paid advertising. Instead, the ads from candidates and groups that support them barely acknowledge Paul. The only ad now airing that remotely attacks Paul shows a picture of him alongside pictures of Minnesota U.S. Rep. Bachmann, Gingrich and former Sen. Rick Santorum of Pennsylvania without naming any one of them individually.

"If Washington's the problem, why trust a congressman to fix it?" says the ad, from Perry, the governor of Texas.

It's not that Paul isn't a threat to win Iowa. Two new polls Wednesday found him neck and neck with Romney atop the field.

Also, Paul has a deep statewide organization to get people to attend and participate in the caucuses, town hall-like meetings in which it's crucial to know the rules.

His rivals might be hoping that the news media will do the work for them.

More importantly, none of the Republican candidates feels the need to spend any ad money knocking Paul down. That's most true for Romney and the independent group that supports him.

Long suspect to conservatives, the former Massachusetts governor wants to keep conservatives divided and doesn't want to hasten the day that they coalesce around one candidate, particularly Gingrich or Perry. Though each has problems – Gingrich also raises alarms with conservatives and Perry stumbled through debates – they have the national name or access to money to wage a long-term challenge to Romney.

Paul, on the other hand, might not be able to rally the conservatives who dominate the party. His vow to slash federal spending by $1 trillion in one year is popular, but his promise to pull back U.S. forces from overseas – and keep them home – is anathema in the broader party.

"I don't think conservatives would embrace Ron Paul as the standard-bearer," said Keith Appell, a Virginia-based conservative strategist. "The calculation is that it's not going to be Ron Paul, so why antagonize his people? They're looking to bring them into their tent later."

The gambit has risks, though. An Iowa win almost certainly would help Paul raise more money and more volunteers, perhaps enough to challenge someone such as Romney coast to coast through the winter and into the spring. It's notable that Paul was the only candidate other than Romney to qualify for the primary ballot in Virginia, which will vote March 6; it speaks to his organization.

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Reach Steven Thomma at sthomma@mcclatchydc.com

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