There's a number hovering around the GOP presidential race: 1,144. That's the magic number of delegates needed to secure the party's nomination.
Former Massachusetts Gov. Mitt Romney has a little less than half that number right now, but he's still ahead of his closest rival, former U.S. Sen. Rick Santorum.
Santorum is a threat, however, so the two candidates seem to be sharpening their math skills.
In many Republican primaries and caucuses - from Missouri, which began Saturday, to Puerto Rico on Sunday, and on to Illinois on Tuesday - the winner doesn't clean up. The delegates are awarded proportionally.
[Santorum] has the potential for a very strong run of wins, and success can bring some delegate rewards down the line.
It's a new system for Republicans and it's led to what could be called "Moneyball politics." In the film and book Moneyball, the manager of the Oakland A's baseball team used mathematical calculations to recruit players instead of the tried and true methods recruiters used for years.
In the end, it's math that will likely win the GOP race.
A Master Strategy
All of this is very familiar to former Democratic strategist Jeff Berman. During the 2008 presidential primary, Berman was the mastermind behind President Obama's delegate strategy. He wrote about it in his new book, The Magic Number.
Berman, as one of the foremost experts on the arcane, byzantine rules of the Democratic Party, was Obama's secret weapon. When it comes to the way political parties nominate candidates, he changed the game.
Berman joined the campaign in the spring of 2007, about a year earlier than where we are now in this cycle. He tells weekends on All Things Considered host Guy Raz that he spent several months looking at detailed data on all the states, their congressional districts, the order of the primaries, the possibility that one outcome would affect another and what the allocations of delegates would be whether they won or lost.
Berman also called and spoke with experts throughout the country, looked at demographics, voting histories and cultural attributes to try and figure out how that district would vote.
"Then I could target those districts in those states where I thought we were close to either winning more delegates or losing a delegate," Berman says, "and then built that together into a master strategy."
It's hard to emphasize how new this model was in presidential politics. Before 2008, conventional wisdom was that you campaigned long and hard in the big delegate states: Ohio, Pennsylvania and Florida. Lock those up, and you win the nomination. You didn't waste your time running grassroots operations in places like Louisiana, Nebraska, Washington state and the Virgin Islands.
Those were the places that, in early February 2008, using Berman's strategy, Obama swept. That streak continued with Obama winning contests in Maine, Virginia, Maryland, Washington, D.C., and Hawaii.
"Running that table for that two-week period, that's when we built a lead of about 150 delegates ... from that point on my mission was to hold that lead," Berman says.
Hold the lead he did, and Obama secured the Democratic Party's nomination on June 3.
The GOP's Math Race
Berman's legacy is that primaries are now a lot about math. Because of that, he believes when it comes to the Republican race, it is still very much up for grabs even with Romney's delegate lead.
"The challenge for [Rick Santorum] is to maintain his political momentum, which he now has having won Alabama and Mississippi," he says. "He has the potential for a very strong run of wins, and success can bring some delegate rewards down the line."
Berman says the tight delegate battle, however, will likely continue until the end of the primary season in June, and a presumptive nominee won't be crowned until then.
Former House Speaker Newt Gingrich trails both Romney and Santorum in the delegate race, and he's under a lot of pressure to bow out. New York Magazine political writer Jonathan Chait tells NPR's Raz that from Gingrich's perspective, it might make more sense to go the distance and become the kingmaker at the convention.
"Gingrich is dividing the conservative alternative to [the] Romney vote, and he's prevented Romney from having to face a united conservative front," Chait says. "So Gingrich's continued campaigning is helping Romney ... maintain his status as front-runner without making it over 50 percent in many states at all."
If he were Gingrich, Chait says he'd continue to take votes from Santorum and then go to Tampa, Fla., where the Republicans will hold their party's convention this summer, and deliver his delegates to Romney in the hopes of a reward. Chait says Gingrich should have a back-channel discussion with Romney and ask how they can help each other.
"But, you never know with Newt Gingrich," he says.