There is a way to think about the up-and-down GOP nomination fight that at least partially explains its volatility and the seemingly endless array of short-lived challengers to front-runner Mitt Romney as well as Romney's surprising resilience.

It's been the battle between the rationals and the notionals.

For more than a year, Rick Santorum has labored to cast himself as an outsider ready to go to Washington to challenge business as usual, which makes it all the more puzzling why he decided to use the crucial debate in Mesa to sound like the ultimate Washington insider. Over and over again, Santorum came off as a defender of Congress, a champion of earmarks and a master of legislative minutiae.

Legislative ratings, Title X, Title XX, earmarks, voting for things you opposed - these are the things that the former Pennsylvania senator talked about. At one point, his tortured explanation prompted Mitt Romney to admit -- or taunt -- he hadn't understood what Santorum was talking about. At other points, his inside-Washington talk and use of legislative jargon set him up for jabs and jibes from Rep. Ron Paul.

It could not have been what Santorum wanted to do in what could be the final Republican debate, the first one held since Santorum surged into the lead in many polls. Perhaps his worst moment was his attempt to explain why he voted for No Child Left Behind even though he opposed it. There were echoes of John Kerry's "I voted for it before I voted against it" only without Kerry's coherence. He said he voted for it because President George W. Bush asked him to do so. "I have to admit I voted for that. It was against the principles I believed in. But, you know, when you're part of the team sometimes you take one for the team, for the leader. And I made a mistake." Not a great answer when you're running to be a leader of a party deeply suspicious of Washington's ways.

 Forget the polls. You don't need to monitor the public opinion polls to track which Republican presidential candidate is surging. All you need to do is see which rival Texas Rep. Ron Paul is attacking - and how sarcastically he gets doing it. In the earlier debates, Paul went after Michele Bachmann, Rick Perry, Mitt Romney and Newt Gingrich. Wednesday night, in Mesa, it was Rick Santorum's turn in Paul's sights.

The first question from CNN moderator John King was why Paul is calling Santorum a fake in his television commercials. With the bluntness that has gained him a cult-like following, the veteran congressman man responded, "Because he's a fake."

Under fire from Republicans for a promise he won't be keeping about cutting the deficit, President Obama might consider emulating Franklin D. Roosevelt, who found himself in a very similar bind eight decades ago. In October 1932, Roosevelt told a crowd in Pittsburgh that he would balance the budget and cut government spending by 25 percent in his first term. But when he got in office, the only way to combat the Depression was to increase spending.

It was the right course for governing. But it presented Roosevelt with a real political challenge when he was running for a second term and returning to Pennsylvania. He asked speechwriter Sam Rosenman how to handle questions about the broken promise.

In the almost six decades that Fidel Castro has ruled Cuba, Republican presidential candidates have elbowed each other and fought to portray themselves as the toughest on Castro - until Thursday night when Rep. Ron Paul showed again that he is quite willing to be different. To a question suggesting that the United States has not been involved enough in influencing governments in Latin America, Paul called for an end to the half-century-old U.S. trade embargo of Cuba.

"Free trade is an answer, the answer to a lot of conflicts around the world," he said. ""I'm always promoting free trade. And you might add Cuba, too. I think we'd be a lot better off... trading with Cuba." Later in his answer, he added, "I believe with friendship and trade you can have a lot of influence. And I strongly believe that it's time we had friendship and trade with Cuba."

None of the other three candidates - who have been ardently wooing the state's influential Cuban community, most of whom are stridently anti-Castro - jumped in to agree. Former Sen. Rick Santorum indicated he did not agree with Paul's response but turned his answer into an attack on President Obama. The president, he said, has a policy of "siding with leftists, siding with Marxists" and seeking common ground with Castro and Venezuela's Hugo Chavez.

"Angry Newt" took the night off. In a striking role reversal, Newt Gingrich looked more like a firefly than a firebrand in a high-stakes debate Monday night, while rival Mitt Romney called the surging former House Speaker a disgraced, influence-peddling, Washington insider.

Somebody must have awakened the cool-and-nonchalant Romney out of his debate slumber and told him the GOP nomination was slipping away. Gingrich stunned the political world -- and frightened much of the GOP establishment -- with a landslide victory in South Carolina on Saturday night that erased Romney's lead in national and Florida polls.

Former House Speaker Newt Gingrich finished an astonishing comeback Saturday night to defeat front-runner Mitt Romney in South Carolina, plunging the Republican Party into a wrenching and potentially lengthy period of soul-searching: Can either of these jokers beat President Obama?

MANCHESTER, N.H. -- The only five men standing between Mitt Romney and the Republican presidential nomination took a walk Saturday night -- attacking each other and the media as the former Massachusetts governor coasted toward the brass ring.

Ron Paul told all Republican voters and the nation why he won't rule out a third-party run if he doesn't win the GOP presidential nomination.

"I want to put as much pressure on them as I can," Paul said at the ABC/Yahoo! News/WMUR debate at Saint Anselm College. "I'd like to see some changes."

That, succinctly, is the clearest, truest and most politically volatile answer Paul has given to the third-party run question. The issue weighs heavily in the GOP general election strategy as Paul could pull 5 percent to 6 percent or more in many swing states - possibly under-cutting GOP efforts to defeat President Obama.

The St. Anselm debate got a little nasty and awfully personal when Rep. Ron Paul stuck by his accusation earlier this week that former Speaker Newt Gingrich is a "chicken hawk" because he accepted deferments that kept him out of military service during the Vietnam War. "At least I went when I was called up," said the 76-year-old Paul who was a flight surgeon in the Air Force in the early '60s.

Paul made the charge on Wednesday when he first talked about Gingrich's reaction when he was eligible for the draft. "Guess what he thought about danger? He chickened out on that and got deferments and didn't even go."

Asked by ABC's George Stephanopoulos if he would again call Gingrich a chicken hawk, Paul responded, "Yeah, I think people who don't serve when they could and they get three or four or even five deferments... they have no right to send our kids off to war."

There must be something in the Iowa air that impels politicians to give off-key speeches after the votes have been cast in the caucuses. Eight years after Howard Dean committed political suicide by screaming out the names of states and four years after Hillary Clinton put so many oldsters on stage that she looked like she was taping an AARP commercial, the Republican candidates Tuesday night gave us so many fresh memories to cherish.

There was Ron Paul declaring, "I'm waiting for the day when we can say we're all Austrians now." The Texas congressman was referring to the Austrian school of economics and his favorite economist, Freidrich von Hayek. But television viewers could be excused if they wondered whether the rally would break into a rousing singing of "Edelweiss." And Paul wasn't finished with the strangeness. In a first in modern American politics, he welcomed to the stage an active-duty soldier wearing his camouflage uniform and critical of American foreign policy.

Corporal Jesse Thorsen, of West Des Moines, is only 28 years old so perhaps he could be excused for forgetting the Defense Department regulation hammered into all members of the Armed Forces that they may not "participate in partisan political... rallies" and "cannot appear at any kind of political forum in uniform." But Paul, himself a veteran, should have known better than to put Thorsen in a position where he could be disciplined by the Army.

A lighter - but also odd - touch was in Rep. Michele Bachmann's valedictory after her sixth place finish. She praised her husband, Marcus, but drew a wince from him when she disclosed that on the day before the caucuses "he was out buying doggie sunglasses for our dog Boomer."

Pundits and rivals have a lot to say about Ron Paul, but the one issue that doesn't come up is his age. His age, you say? That's the least of his electability hurdles.

Still, Paul is 76 -- four years older than John McCain when he won the Republican nomination in 2008, three years older than Ronald Reagan when he became the oldest president to be re-elected in 1984.

The issue of Paul's age was suddenly injected into the political bloodstream Sunday night when presidential historian Doug Wead tweeted: Is Ron Paul too old to run for president? The inevitable answer would seem to be yes, given the statistics and the demands of the job.

A second poll underscores the opportunity that division on the right is creating for Mitt Romney in Iowa. In the NBC/Marist College Iowa survey released Friday, Romney continues to draw only modest support overall - but remains positioned to capture the state because the groups most skeptical of him are fragmenting.

Overall, the poll showed Romney leading with 23 percent, followed by Ron Paul with 21 percent, and then Rick Santorum (15 percent), Rick Perry (14 percent) and Newt Gingrich (13) all bunched closely together. That largely tracks the findings of the CNN/Time/ORC Iowa survey released earlier this week.

In the NBC/Marist poll, like the CNN/Time survey, Romney continues to draw meager support among the party's most ardent elements. The new survey shows him capture just 13 percent among both evangelical Christians and voters who describe themselves as strong tea party supporters.

The latest CNN/Time/ORC surveys released this afternoon for New Hampshire, and especially Iowa, show that on the eve of the first actual voting, the GOP race is reverting to the pattern that has defined it for most of this year: the party's more pragmatic and secular circles are consolidating around Mitt Romney more than the GOP's more ideological and evangelical wings are consolidating around any single alternative to him.

That pattern isn't enough to place Romney in a commanding position - but it does offer him the possibility of a plurality advantage in a fragmented field. The surveys provide a snapshot of the nightmare for the conservative activists most resistant to the former Massachusetts governor: it raises the possibility that he could steamroll to the nomination without ever attracting majority support in the party because the ideological voters most resistant to him fail to ever coalesce behind a single alternative.

These dynamics are most apparent in the results of the new survey in Iowa, which polled 452 GOP likely caucus participants from December 21-24 and December 26-27. Overall the survey shows Romney now leading with 25 percent, followed by Ron Paul with 22 percent; Rick Santorum has surged into third place with 16 percent, followed by Newt Gingrich with just 14 percent. In the most recent CNN/Time/ORC poll from early December, Gingrich led with 33 percent, followed by Romney at 20 percent and Paul at 17 percent.

Newt Gingrich has finally found a politician he considers even worse than the president he calls socialist, anti-colonialist and radical. That would be his fellow Republican Ron Paul.

"I think Barack Obama is very destructive to the future of the United States. I think Ron Paul's views are totally outside the mainstream of virtually every decent American," Gingrich said Tuesday in a CNN interview with Wolf Blitzer.

Could he vote for Paul? "No." If it came down to Paul vs. Obama? "You'd have a very hard choice at that point."

A bus tour is a great way to experience the under-appreciated glories of Iowa. (Seriously folks, the state is beautiful). It's also a valuable tool in a place that prizes personalized retail campaigning and hasn't seen all that much of it this year - especially from these two leading GOP presidential candidates.

Romney has been tending to his firewall in New Hampshire and trying to seem like he's not working too hard in Iowa lest he be embarrassed on caucus night. Gingrich has played the VIP celeb, counting mainly on debates to make him a contender.

That's changing this week in the final stretch. Romney gives a speech Tuesday night in Davenport and launches a three-day bus tour the next morning.  Gingrich and his wife Callista will be riding a bus for the duration. Their "Jobs and Prosperity" tour starts Tuesday with 11 stops in its first three days. 

That's small potatoes next to the 10 stops Michele Bachmann has scheduled for Tuesday alone. Bus tours have been a staple for Bachmann as well Rick Santorum, Rick Perry and Ron Paul - the other candidates competing hard in Iowa. 

Polling in the unsettled race suggests Paul, Romney or Gingrich could win it. Bachmann and Santorum, short on money, are looking for a better-than-expected finish to keep them afloat. If Perry makes a surprise show of strength, he could re-emerge as the chief alternative to Romney.

Adam Smith of the Tampa Bay Times pointed out this week that some 370,000 Florida Republicans already have requested absentee ballots for that state's Jan. 31 primary -- more than all the Republicans who voted in the 2008 Iowa and New Hampshire contests combined.

Still, the snowball effect of doing well in Iowa and New Hampshire cannot be ignored. Thus the bus tours, the ads, the descending of the national media. 

The most accurate indicator of how candidates will fare Jan. 3 in Iowa is the Des Moines Register poll conducted by Selzer & Co. of Des Moines. In the final days of 2007, it was the only poll to pick up on Barack Obama's growing lead over Hillary Clinton, due to his success at bringing new voters into the arcane caucus process.

The caucuses that year were also held Jan. 3 and the final poll was released Dec. 31 based on interviews conducted Dec. 27-30. Obama led Clinton 32 percent to 25 percent, a margin almost identical to his 8-percentage-point victory over Clinton and John Edwards a few days later.

The Register won't disclose when it is in the field this year. But judging by the 2007 time frame, interviewers will be talking to Iowa Republicans throughout this week of intensified candidate activity, advertising and press coverage.

Did Paul peak too soon? Did Romney and Gingrich wait too long to make a full-court press, or are they coming on strong just in time? The Register poll will be our best clue to what is likely to happen next week when Iowa Republicans cast the first votes of the primary season.