DES MOINES — As the Freedom Summit marks the unofficial start of the 2016 Republican presidential campaign here in Iowa, the race is already too sprawling, with too many characters and too many crosscurrents, to have a single theme. But here are a dozen keys to understand what is happening now:

1. The candidates who have run before — Mitt Romney, Mike Huckabee, Rick Santorum — all think they can get their teams back together for another race. They can't. Each man has been in touch with staff and supporters from 2008 and 2012, with the assumption that the people who were willing to work for them back then will do so again in 2016. But the world has changed; issues have changed and new candidates have emerged. Moderates who backed Romney now have Jeb Bush and Chris Christie to consider, while conservatives who backed Huckabee and Santorum have Ted Cruz and Ben Carson. Even if the veterans run again, they won't be able to recreate what they had before. They'll have to do something different.

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2. Chris Christie is in better shape than you think. There was a widely-held assumption that Christie's Jersey Guy persona wouldn't play well in Iowa — that he is just too hot and too confrontational to get along with a bunch of nice Midwesterners. But it turns out a lot of Iowa Republicans actually like Christie, even if they're not quite ready to support him. Christie connects with audiences in Iowa just like elsewhere in the country, and more importantly, Iowa Republicans really want someone to fight for them in the next campaign. Most felt Romney just wouldn't take it to President Obama in 2012, so now Christie is OK with them as long as they believe he will give Democrats hell.

3. Foreign policy has become as important as social issues, and that means people will listen to John Bolton. One simple sentence explains the new prominence of foreign policy in the race: It's a dangerous world. With the rise of the Islamic State in Iraq and Syria, the Paris attacks, the troubling resilience of terror networks, worrisome developments in Russia, the challenge of China — when all of those are combined with the sense that the Obama administration either doesn't know what is doing or is badly misguided, or even worse, Iowa conservatives have become deeply concerned about foreign policy. Then remember that the governors who are running have no foreign policy experience, and the senators are all recent arrivals on the national stage. Who knows enough about the world today to address those problems? Enter John Bolton, the former Bush administration United Nations ambassador who is deeply versed in foreign affairs. A number of conservatives would welcome Bolton's presence in the GOP debates to raise the level of foreign policy discussion. Yes, they know he is pro-gay marriage, and they will never approve of that. But they will listen respectfully to what Bolton has to say.

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4. Romney loyalists are deeply ambivalent about another run. A remarkable number of former Romney staff and supporters admire him tremendously and remain steadfastly loyal. They have told him as much on a number of occasions over the last few years. But now some worry that Romney has perhaps misinterpreted their heartfelt expressions of support as encouragement to run again in 2016. They still believe he would be a good president, but they do not think it will be possible for Romney to rid himself of 2012 baggage in order to get the clean start necessary to run a winning campaign.

5. The Bush family network isn't as strong as some believe. There has been much talk of the vaunted Bush political machine, which is said to give Jeb Bush a big advantage even before the 2016 race officially begins. Jeb Bush himself has been calling donors and has told some of them that he hopes they will again support "the family." But the fact is, it has been a while since the Bush machine was in operation here in Iowa. It was last up and running in 2004, for the re-election of George W. Bush, and last at work for the caucuses in 2000, for W's first run. For the 2016 race, that means the machine has been out of action for a long time. Many Bush donors from 2000 and 2004 became Romney donors in 2008 and 2012. They have conflicted loyalties, and not all of them will rejoin the family.

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6. Scott Walker doesn't have to be great on the stump to do well. As a lot of Republicans see it, the Wisconsin governor is the most accomplished candidate in the race. Who can match his achievement staring down the mighty public-sector unions and then winning a recall and re-election in a blue state? For Republicans, those are simply huge victories. Now, as the campaign begins, Walker's record means GOP voters will cut him a little slack in the charisma and oratory department. It's fair to say that Walker does not electrify a crowd. But his GOP cred as the man who took on the unions and the armies of the left means he can win over an audience even if he can't speak like Ted Cruz.

7. Rick Santorum is in very bad shape. One would think the former Pennsylvania senator, as the (narrow) winner of the 2012 caucuses, would have a lot of standing for another race. He doesn't. Many Republicans believe Santorum's earlier success was the result of a set of peculiar circumstances involving a weak and fragmented 2012 field. They admire how hard he worked that year, traveling around Iowa with a thoroughness and intensity that no other candidate could match. But they don't see it happening again with a stronger field in 2016. And they don't see Santorum surviving a loss in the state he won before.

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8. Many insiders do not expect Marco Rubio to run, and if he does, they think he's doomed. A lot of political types were surprised by the ABC News report Friday that Rubio has instructed his staff "to proceed as if he is running for president." They had expected instead that Rubio would choose to run for re-election to the Senate (which he still might to do). But even if Rubio runs for president, they don't see him overcoming his authorship of comprehensive immigration reform in the Senate. First, Republicans deeply oppose what's in the bill. Second, they saw Rubio as the junior partner in the enterprise, bested and pushed around by Democrats. That's not good for a Republican running for president.

9. Rick Perry will get another chance, but it will be a very narrow one. How could the former Texas governor ever come back after his gaffe-ridden 2012 campaign? It's likely that most observers, if asked in 2013, would have said no one could recover from that. But Perry has worked hard to present himself as a different man this time around, one who has taken the time to study the issues. The problem is, even if he does better, Perry will have an incredibly slim margin of error. The first gaffe and it will be "Oops" all over again.

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10. Rand Paul still has to deal with the sins of his father, or at least of his father's supporters. There are still a lot of bad feelings among Iowa Republicans about the Paulite takeover of the state GOP in 2012. Local politicos regard it as a disaster which did enormous damage to the party all the way until last summer, when mainstream Republicans finally reclaimed the organization. The GOP is doing well again, but a lot of resentments remain, and Rand Paul will inherit some of them. He'll have to find a way to deal with it if he wants to broaden his appeal.

11. Ben Carson is a big draw, but is viewed with disdain by political professionals. The doctor who gained fame by taking on President Obama draws large crowds and devoted followers among some Iowa conservatives. They are the type of voters who also like Ted Cruz, but see something extra in Carson that captures their hearts. On the other hand, some Republican political pros see Carson as an entirely untested amateur whose candidacy is guaranteed to collapse. The intensity of a presidential campaign mercilessly exposes a candidate's flaws, they say, and Carson's implosion is guaranteed to come, probably sooner rather than later.

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12. You know what Bobby Jindal said about Muslim "no-go zones" in Europe, a statement that resulted in Jindal being criticized and mocked by mainstream commentators? It turns out many social conservatives in Iowa really liked it. To them, Jindal was warning about the danger of enclaves of unassimilated Muslim populations in an age of Islamic radicalism, a problem they fear could be in store for the United States. Jindal, who is himself the model of an assimilated American from an immigrant family, not only did not suffer from his remarks but instead benefited from them.

Those are 12 factors at play in the race now. One could easily list 12 more, and 12 more after that. It's going to be a very complicated campaign.

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