At the private air terminal at Logan Airport in Boston early Wednesday, men in unwrinkled suits sank into plush leather chairs as they waited to board Gulfstream jets, trading consolations over Mitt Romney’s loss the day before.

"All I can say is the American people have spoken," said Kenneth Langone, the founder of The Home Depot and one of Romney’s top fundraisers, briskly plucking off his hat and settling into a couch.

The biggest single donor in political history, casino billionaire Sheldon Adelson, mingled with other Romney backers at a postelection breakfast, fresh off a large gamble gone bad: Of the eight candidates he supported with tens of millions of dollars in contributions to super PACs, none were victorious Tuesday.

And as calls came in Wednesday from some of the donors who had poured more than $300 million into the pair of big-spending outside groups founded in part by Karl Rove — perhaps the leading political entrepreneur of the super PAC era — he offered them a grim upside: Without us, the race would not have been as close as it was.

The most expensive election in U.S. history drew to a close this week with a price tag estimated at more than $6 billion, propelled by legal and regulatory decisions that allowed wealthy donors to pour record amounts of cash into races around the country.

But while outside spending affected the election in innumerable ways — reshaping the Republican presidential nominating contest, clogging the airwaves with unprecedented amounts of negative advertising and shoring up embattled Republican incumbents in the House — the prizes most sought by the emerging class of megadonors remained outside their grasp. President Barack Obama will remain in the White House, and the Democrats have strengthened their lock on the Senate.

The election’s most lavishly self-financed candidate fared no better. Linda E. McMahon, a Connecticut Republican who is a former professional wrestling executive, spent close to $100 million — nearly all of it her own money — on two races for the Senate, conceding defeat Tuesday for the second time in three years.

"Money is a necessary condition for electoral success," said Bob Biersack, a senior fellow at the Center for Responsive Politics, which tracks campaign spending. "But it’s not sufficient, and it’s never been."

Even by the flush standards of a campaign in which the two presidential candidates raised $1 billion each, the scale of outside spending was staggering: More than $1 billion all told, about triple the amount in 2010.

Obama faced at least $386 million in negative advertising from super PACs and other outside spenders, more than double what the groups supporting him spent on the airwaves. Outside groups spent more than $37 million in Virginia’s Senate race and $30 million in Ohio’s, a majority to aid the Republican candidates.

The bulk of that outside money came from a relatively small group of wealthy donors, unleashed by the Supreme Court’s Citizens United decision, which allowed unlimited contributions to super PACs. Harold Simmons, a Texas industrialist, gave $26.9 million to super PACs backing Romney and Republican candidates for the Senate. Joe Ricketts, the owner of the Chicago Cubs, spent close to $13 million to bankroll a super PAC attacking Obama over federal spending.

Bob Perry, a Texas homebuilder, poured more than $21 million into super PACs active in the presidential race and the Senate battles in Florida and Virginia, where Democrats prevailed. A donor network marshaled by Charles and David Koch, billionaire industrialists and conservative philanthropists, reportedly sought to raise $400 million for tax-exempt groups that are not required to disclose their spending.

Adelson’s giving to super PACs and other outside groups came to more than $60 million, although in public Adelson did not seem overly concerned about the paltry returns on his investment.

"Paying bills," Adelson said Tuesday night when asked by a Norwegian reporter how he thought his donations had been spent. "That’s how you spend money. Either that or become a Jewish husband — you spend a lot of money."

Flush with cash, Republican-leaning groups outspent Democratic ones by an even greater margin than in 2010. But rather than produce a major partisan imbalance, the money merely evened the playing field in many races.

In several competitive Senate races, high spending by outside groups was offset to a large extent with stronger fundraising by Democratic candidates, assisted at the margins by Democratic super PACs. For much of the fall, Obama and Democratic groups broadcast at least as many ads, and sometimes more, in swing states than Romney and his allied groups, in part because Obama was able to secure lower ad rates by paying for most of the advertising himself. Romney relied far more on outside groups, which must pay higher rates.

Haley Barbour, a former Mississippi governor who helped Rove raise money for American Crossroads and its sister group, Crossroads Grassroots Policy Strategies, said that without a blitz of coordinated anti-Obama advertising in the summer, the campaign would not have been as competitive.

"I believe that some of that money actually kept Romney from getting beat down by the carpet-bombing he underwent from the Obama forces," Barbour said. "I did look at it more as us trying to keep our candidates from getting swamped, like what happened to McCain."

Some advocates for tighter campaign financing regulations argued that who won or lost was beside the point. The danger, they argued, is that in the post-Citizens United world, candidates and officeholders on both sides of the aisle are far more beholden to the wealthy individuals who can finance large-scale independent spending.

"Unlimited contributions and secret money in American politics have resulted in the past in scandal and the corruption of government decisions," said Fred Wertheimer, the president of Democracy 21, a watchdog group. "This will happen again in the future."

But Wednesday, at least, the nation’s megadonors returned home with lighter wallets and few victories.

As the morning wore on at Logan Airport, more guests from Romney’s election-night party at the Boston Convention and Exhibition Center trickled in, lugging garment bags and forming a small line at the security checkpoint.

"It’s going to be a long flight home, isn’t it?" said one person, who asked not to be identified.

Investor Julian Robertson, who held fundraisers for Romney and gave more than $2 million to a pro-Romney super PAC, arrived with several companions. Robertson spotted an acquaintance: Emil W. Henry Jr., an economic adviser and a fundraiser for Romney, to whom Robertson had offered a ride on his charter.

"Aww, group hug," Henry said.

© 2012 The New York Times Company