SPRINGFIELD, Mo. • The Election Day war room of Republican Roy Blunt buzzed with activity about 10:15 a.m. when social media consultant Pete Snyder sent an urgent e-mail to campaign manager Andy Blunt, the candidate's son.

Snyder, a pioneer in using the online world to monitor and shape a candidate's reputation, saw a spike in activity from the campaign of Democrat Robin Carnahan.

"Robin is doubling down," Snyder wrote. "Her team saw what we are doing, and this is a last minute attempt to stave off the stake to her heart."

Snyder asked for and received immediate authorization to spend $10,000 on online advertisements targeting St. Louis County and Jackson County voters.

Thus began an online "arms race" that might have played some part in helping Blunt win the race for the U.S. Senate by a shocking 14 percentage point margin.

It's part of the new world of hand-to-hand Internet combat that made the 2010 election different from any previous one, and it set the scene for changes that will be made as politicians realize how to harness the power of the online world.

Missouri's Senate race was awash in online strategies in both the Carnahan and Blunt campaigns, with Twitter, Facebook and iPhone apps all playing a role until the polls closed.

"It used to be that all the consultants didn't know what to do on Election Day," Snyder said in an interview a few hours after the Blunt campaign blew through its Tuesday budget in an attempt to react to what Snyder was seeing online.

But one look at the high-tech Blunt war room shows how Election Day politics have changed forever.

"What we are seeing right now is unprecedented," Snyder said in his e-mail to Blunt. "This will be the highest trafficked election online in history."

In one ballroom at the University Plaza, about 80 young Blunt volunteers with laptops and cell phones were taking information from other volunteers monitoring precincts at about 1,000 polling places across Missouri. As targeted voters came in and cast their ballots, they were recorded into the database, which was then turned into a series of graphs blasted on a big screen in an adjacent room.

That's where Blunt, Snyder and other consultants and confidants viewed results and decided how to get more of the "right" voters to the polls.

Part of their get-out-the-vote strategy was to use social media and Internet ads to motivate voters of certain demographics to vote for Blunt.

The Blunt camp regularly finished atop a daily tracking of national politicians using Twitter and Facebook and other social media software to spread specific campaign messages. Part of the Blunt strategy was to target women over 40 — a key Carnahan demographic — in Internet ads on Facebook and "mom blogs."

By the time Blunt was on the stage in the convention hall next door celebrating, he and his top campaign officials were pointing to their work on the Internet as a key to their win.

Campaign chairwoman Ann Wagner, the former co-chairman of the national Republican Party, has seen a lot of high-level politics. But the way the Blunt campaign harnessed the Internet was something other campaigns will be modeling in coming years, Wagner said: "It's the biggest change I've seen in politics."

It's the sort of change that allowed Snyder to make that last-minute strategic Internet purchase to affect voting patterns.

Early Tuesday, Snyder noticed the Carnahan camp had made a big buy of Google advertising, targeting voters in the urban counties of St. Louis and Jackson. The way Google ads are priced is linked to supply and demand, so with Carnahan making such a big last-minute buy, the price for such ads doubled overnight.

"Today, Carnahan's people woke up," Snyder said. "It was an arms race."

Within 40 minutes, he had spent the $10,000.

And within another couple of hours, the price of the targeted Google ads had dropped significantly, and the Carnahan ads had mostly disappeared.

The polls were still open, and the results were hours away. But Snyder saw the writing on the wall. It was a strategic moment on the final day of a 20-month campaign, but it could serve as a metaphor for what went right for one camp and wrong for another.

Said Snyder, a confident smile on his face: "We won that battle."