Baseball and politics are two of David Plouffe's passions. So it was natural that his love for one game reinforced something that proved crucial in the other: Singles can score runs.

As Sen. Barack Obama's campaign manager, Plouffe, 41, was the mastermind behind a winning strategy that looked well past Super Tuesday's contests Feb. 5 and placed value on large and small states.

The campaign had the money to make such a potentially low-yield wager, and Plouffe had long understood that the Democratic Party's complex system for apportioning convention delegates meant winning even one congressional district in a state could help generate the total needed to reach the magic number.

From his Chicago office, Plouffe (pronounced

Pluff

) sent resources to states such as Nebraska, Idaho and North Dakota that Sen. Hillary Rodham Clinton virtually ignored, putting extra emphasis on those with lower-turnout caucuses instead of primaries.

The plan, in his head at least as far back as late 2006, was partly out of necessity, because of Clinton's advantages in big states.

The strategy proved itself in the two weeks after Feb. 5, as Obama won 11 contests in a row and achieved a delegate lead he would never lose.

Marking one of the biggest upsets in U.S. political history, Obama himself saluted his behind-the-scenes general at the start of his victory speech last week in St. Paul, Minn.

"Thank you to our campaign manager, David Plouffe, who never gets any credit, but who has built the best political organization in the country," Obama said.

As Obama's campaign turns to the general election, Plouffe will lead the way - against someone he listed in 2003 in a Washington political journal as his favorite Republican, Sen. John McCain.

In a campaign filled with alums from the 2004 presidential efforts of Sen. John Kerry and former Rep. Dick Gephardt, Plouffe comes from the Gephardt branch. In 2003 and early 2004, he was a senior adviser to Gephardt's brief bid.

Plouffe can almost seem shy compared with more gregarious campaign personalities. He is a business partner with media strategist David Axelrod and worked with him on Obama's winning 2004 Senate campaign. But Plouffe, unlike Axelrod, rarely appears in front of television cameras.

"He's the most disciplined and focused person I have ever met in politics," said Democratic strategist Steve Elmendorf, who previously supported Clinton. "It is very easy to get distracted by the press and donors and activists. David just has a great filter and he doesn't let any of the noise bother him. In a presidential campaign, that's a rare talent."

"He is smart and scrappy and doesn't bring a huge amount of ego to the table," said JoDee Winterhof, a political strategist who has worked with and competed against him.

Like a baseball manager who knows it is a long season, Plouffe tends to avoid highs or lows, similar to his candidate. While his boss cheers for the White Sox, Plouffe prefers the Phillies (a reflection of a childhood in Delaware).

Plouffe's campaign-office door is always open, but his wallet isn't.

Although Obama's campaign has shattered fund-raising records, Plouffe, the survivor of congressional campaigns that have run short on money, is well-known for his frugality. Many staffers, for example, double up in hotel rooms while on the road.

Plouffe also understands the workings of the media and has offered lines for Obama speeches that were powerful enough to make the final cut, a skill he honed working on many campaigns and with Axelrod.

In politics since college, he had an earlier big win in New Jersey, where he managed the campaign for Bob Torricelli to fill Bill Bradley's U.S. Senate seat in 1996.

After his work as executive director of the Democratic Congressional Campaign Committee, Plouffe joined Axelrod's consulting business in 2000. He worked with Axelrod on the successful 2006 campaign of Deval Patrick for Massachusetts governor.

"He has the capacity to handle more details in his head at one time than anyone I know," Axelrod said.

Plouffe is fascinated by numbers, Democratic consultant Bill Carrick said: "He just has an insatiable appetite for this stuff and he could keep all of it in his head."

Elmendorf said he looked for more of the same from Plouffe in the general election. "It was probably the best-run presidential campaign in a generation," he said. "They will have a plan. It may not be clear yet, but they will execute it."