5 posibles escenarios

Basándose en precedentes históricos, Nate Silver presenta 5 posibles escenarios en los que pueden desembocar las primarias republicanas:

Interpretation No. 1: It’s All Over but the Concession Speeches.

What Happens Next — The Short Version: Mr. Romney gets some real and sustainable momentum from Florida and wraps up the nomination quickly and easily.

What Happens Next — The Long Version: Mr. Romney gets a lift in national polls and takes a considerable lead in most surveys. He easily wins next week’s caucuses, building further momentum. He begins to roll out more endorsements, including some important and surprising ones from conservative leaders who are trusted by the Republican base. Rick Santorum drops out and either endorses Mr. Romney outright or otherwise makes clear that he considers Mr. Romney the most acceptable choice. Newt Gingrich either drops out or reverts to running a half-hearted campaign.

Popular attention to the nomination race dwindles, and the news media’s focus shifts to the general election. The outcome of Super Tuesday is a foregone conclusion. Any further losses that Mr. Romney takes are a result of special circumstances — for instance, to Mr. Gingrich in Mr. Gingrich’s home state of Georgia.

Precedent: The 2000 Republican race is the best example of a contest in which the front-runner, George W. Bush, lost a couple of early states but was perhaps never in any real danger of losing the nomination.

(...) Interpretation No. 2: Florida Is the New Normal.

What Happens Next — The Short Version: Florida is the best benchmark for the Republican race going forward: Mr. Romney has a clear but not overwhelming advantage. The race may continue for some time, particularly depending on the preferences of Mr. Gingrich, but in such a way that the ultimate outcome is not seriously in doubt.

What Happens Next — The Long Version: Mr. Romney endures a few more losses along the way, including in some midsize states, especially in the South. However, he wins the clear majority of contests. His advantages are accentuated by his performance in caucus states and his support among automatic delegates (the Republican equivalent of “super delegates”).

Volatility in the race decreases. Mr. Romney holds a stable if not overwhelming lead in national polls. There may be a point or two at which Mr. Romney loses a state unexpectedly, but this is not accompanied by a pronounced decline in his national poll ratings.

Meanwhile, some swing voters grow impatient with Mr. Gingrich, especially as his path to the nomination becomes more mathematically implausible. Some of them begin to support Mr. Romney just to get the contest over with.

Precedent: The 1992 Democratic race featured a gadfly candidate, Jerry Brown, who was never any real threat to win the nomination. Bill Clinton, the front-runner that year, did endure a handful of losses to Mr. Brown, but he never lost his lead in national polls and was able to place most of his focus on November.

(...) Interpretation No. 3: Anybody but Romney? Certainly Not Newt.

What Happens Next — The Short Version: Support for Mr. Gingrich erodes more than support for Mr. Romney builds. There is a limited window of opportunity for Mr. Santorum, but he needs considerable luck to take advantage of it. Mr. Romney probably wins, perhaps fairly easily, but there is some drama along the way.

What Happens Next — The Long Version: Mr. Gingrich experiences a significant decline in national polls and does poorly in the caucus states. He gets no more support from his “super PAC,” and his campaign becomes increasingly unfocused.

However, Republicans are not necessarily ready to gravitate to Mr. Romney. Instead, they give Mr. Santorum another look, and he is buoyed by some modest success like a strong finish in the Minnesota caucus or a win in the Missouri beauty contest primary.

Mr. Santorum is competitive in several Super Tuesday states, including Ohio, and proves to be a reasonably strong match for Mr. Romney in the debates. Mr. Gingrich is not eager to drop out, but some of his supporters gravitate toward Mr. Santorum as he comes to be seen as more viable, perhaps forcing the issue.

Still, Mr. Santorum faces some considerable disadvantages: he lacks resources, and is always running from behind in the delegate count. He has a chance to win if everything breaks just right, but more likely concedes after a failed last stand in a state like Texas or Wisconsin on April 3. Mr. Romney takes some limited damage for the general election, but of the kind that would make a difference only in an extremely close race.

Precedent: In recent nomination races, there has not been a good example of a “third wheel” candidate coming from behind to emerge with the nomination. Instead, this scenario bears more resemblance to the period between about 1968 and 1976, when the nomination process was in a transitional phase. Jimmy Carter in 1976, for instance, was not an ideal Democratic nominee, but prevailed after “anybody but Carter” efforts fizzled. The closest thing to an exception is probably 1972, when George McGovern came from behind to win the Democratic nomination, but Mr. McGovern took considerable advantage of the party’s new delegate allocation rules, which he had helped to design.

(...) Interpretation No. 4: Rinse, Lather, Repeat.

What Happens Next — The Short Version: There continues to be considerable volatility in the Republican race and any advantage that Mr. Romney has is tenuous. But he retains a slight edge in national polls and a clearer one in the delegate math. Mr. Gingrich remains his main rival.

What Happens Next — The Long Version: Mr. Romney gets little bounce in national polls from Florida or if he does, it fades quickly. He loses a couple of states in February, and a number of them on Super Tuesday. Still, Mr. Romney also wins his share of states and remains reasonably well-prepared for a war of attrition. The race remains volatile, and Mr. Romney endures some potential general election damage. But he is something like a 75 percent or 80 percent favorite to emerge with the nomination, with the victory probably occurring well before the convention.

Precedent: The 1984 Democratic race was reasonably close between Walter Mondale and Gary Hart. That race bears some resemblance to this one, in that Mr. Mondale was an establishment-backed nominee whom rank-and-file voters had limited enthusiasm for. Still, Mr. Mondale had a reasonably clear edge throughout the race in the delegate count, benefiting from this organizational advantages in caucus states, and he wrapped the nomination up before the convention.

(...) Interpretation No. 5: Florida Was a Fluke.

What Happens Next — The Short Version: A fight to the finish. Mr. Romney’s win in Florida resulted from idiosyncratic circumstances and has little predictive power for future states. He might win the nomination nevertheless, but he and Mr. Gingrich have assets and liabilities that roughly balance each other out.

What Happens Next — The Long Version: National polls continue to point toward a highly ambiguous result. Mr. Romney takes some hard-to-excuse losses in February — perhaps he wins Nevada because of his advantage among Mormon voters, but he loses either Arizona or Michigan on Feb. 28. Then his performance on Super Tuesday is underwhelming, and he loses Ohio. Mr. Romney has a number of opportunities to rebound but may or may not take advantage of them. Mr. Santorum drops out of the race — and although he might not endorse Mr. Gingrich, most of his voters wind up in Mr. Gingrich’s camp.

There is some chance of a brokered convention under this scenario, and an outside chance of a compromise candidate who is not running for president currently.

Precedent: Evenly matched fights to the finish have been rare; the closest thing to an exception was the 2008 Democratic nomination race.

Leed todo el trabajo para conocer las evidencias a favor y en contra de cada escenario.