How to untangle the politics of Super Tuesday primaries

For the past year, a large field of presidential candidates has lavished attention on just a few early primary and caucus states. Suddenly, on the eve of the biggest primary day in United States history, the calculus is reversed: A handful of candidates are competing in almost two dozen states, spread across the country.

The stakes going into Feb. 5, or "Tsunami Tuesday," could not be higher. In each party, more than 80 percent of the total delegates needed to secure the nomination are up for grabs. And the system for allocating delegates is even more complicated than that of the Electoral College, with delegates awarded mostly by congressional district. An important exception is the eight Republican contests that are winner-take-all by state.

Never before have the experts on each campaign who know the rules of delegate allocation in every state been so important. The scramble for delegates is on, district by district.

Democratic Illinois Sen. Barack Obama, for example, does not expect to win New York. "But do we expect to pick up delegates because we have a strong operation and a grass-roots following in places like Brooklyn and Harlem and the Bronx? Absolutely," says campaign spokeswoman Jen Psaki.

Because none of the 22 Democratic states (and American Samoa) or their congressional districts are winner take all, both candidates have reason to compete in every state. District-level delegates are allocated proportionally to the outcome of the vote or caucus result in a congressional district, as long as a candidate reaches a 15 percent threshold, according to national party rules. Statewide delegates are also allocated proportionally.

Another variable is whether the contests are open or closed, whether only registered members of a party may take part. Open contests tend to benefit Obama and Sen. John McCain, who are better at attracting unaffiliated voters and voters from the other party.

Rules are simpler for Republicans. Some of Senator McCain's strongest states are winner take all, including his home state of Arizona, plus New York, New Jersey, Connecticut, and Delaware. Those five states alone account for 234 delegates, not including "superdelegates," giving McCain a cushion of delegates he can reasonably count on going into Tuesday.

For McCain's principal rival, former Massachusetts Gov. Mitt Romney, most of his strongest states are not delegate-rich. With the exception of Mormon-dominated Utah, where he has a lock on the state's 33 delegates, other strong states, including Massachusetts, are not winner take all. Most of Mr. Romney's strong states are holding caucuses, with modest delegate counts and a range of rules on delegate allocation.

One state where Romney could cherry-pick some delegates is California, which awards delegates on a winner-take-all basis by congressional district. The trick there, analysts say, is to identify low-turnout Republican districts that are overwhelmingly Democratic and flood the few Republicans with mail.

But with so many states at stake on Tuesday, Romney will have a hard time using his well-honed organization to win the delegates he needs. McCain, following his victory in Florida, is winning the lion's share of key GOP endorsements.

At this point, "it's not an organization game, it's a momentum game," says GOP pollster Whit Ayres. "There's no way to be sufficiently organized in all the Super Tuesday states."

Even in Florida, Mr. Ayres notes, Romney had a far more sophisticated operation and spent far more money than McCain, but lost anyway. Still, Romney has gone forward with ad buys in key Feb. 5 states, spending a reported $2 million to $3 million, with $1 million in California alone. McCain has relied more on momentum and free media out of campaign appearances in the days preceding Feb. 5, though he is running some TV ads.

Democrats Obama and Clinton have raised far more than the leading Republicans and are spending more on television leading up to Feb. 5. Obama has spent more than $10 million in ads in most of the Feb. 5 states, as well as states holding primaries in the week after – a sign of confidence that he will remain competitive after Tsunami Tuesday. Obama raised a stunning $32 million in January; Clinton has reportedly spent $8 million on ads in 16 of the Feb. 5 states, but had not revealed her January fundraising.

One potential wrinkle out of Feb. 5, given the delegate-allocation rules, is the possibility of a candidate winning more votes in a primary or caucus than his or her main rival, but not winning as many delegates, as happened in the Nevada Democratic caucuses.

"You could have a bit of a disparity between the popular vote and the delegate count, but I think by and large it should be pretty reflective," says Rhodes Cook, a nonpartisan political analyst. "I would be surprised if you had many more examples like Nevada, but I could be wrong."