Campaign spending scrutinized

— -- As the most expensive presidential election in history nears its close, Americans by nearly 3-1 think too much money is being spent on the campaign, and most back limits on how much candidates are allowed to spend.

A USA TODAY/Gallup Poll taken Tuesday finds wide support for public financing of presidential campaigns, including a third who say the current voluntary system should be mandatory.

Even so, Democrat Barack Obama hasn't paid much of a political price for opting out of public financing this year, the first major-party nominee to do so since it was established after the Watergate scandal. Nearly two-thirds of Americans say they aren't sure whether Obama or Republican John McCain are participating in the system.

In the future, presidential candidates are increasingly likely to bypass public funding, says Anthony Corrado, a professor at Colby College in Waterville, Maine, who studies campaign finance.

"I think we're in a position now where candidates are no longer going to look at the public-funding option unless their backs are against the wall," he says.

Obama was to display his financial muscle Wednesday night with a 30-minute campaign infomercial airing on NBC, CBS, Fox and Univision at a cost of more than $3 million.

McCain's campaign is generally limited to the $84 million it accepted in public funds for the general election.

Four in 10 Americans say the nation should maintain the voluntary system, and 32% say candidates should be required to participate. Only 1 in 5 say the system should be eliminated.

However, fewer than 10% of taxpayers now mark the $3 tax check-off box on their tax returns to underwrite the system.

Among other findings:

•Americans by 70%-24% say too much money has been spent on presidential campaigns this year — a record $2.4 billion, according to the non-partisan Center for Responsive Politics.

•Republicans are more than twice as likely as Democrats to support mandatory participation in public financing.

•And those campaign ads dominating the airwaves in battleground states? Two-thirds say they "serve a useful purpose," while 1 in 3 say it would be better if there were no TV ads.