And in states like Florida, Iowa, Nevada and Virginia, where the Romney and Obama forces are roughly matching their spending dollar for dollar, the super PACs are responsible for nearly half the advertising that is benefiting the Republican nominee.

After three weeks of bad news for Mr. Romney — first that he received a negligible bounce from his convention, then that Mr. Obama was overtaking him in the polls and finally that he had been secretly recorded disparaging the president’s supporters as government-dependent freeloaders — the lack of a more forceful advertising offensive is one more way that the Romney campaign finds its message obscured.

Each day that slips by is a loss of precious television time in an air war that is only going to grow heavier and louder, making it difficult for any ad to leave a lasting impact.

“In a world where we know advertising imbalances lend opportunities for persuasion, it is surprising that any campaign would allow imbalances to continue,” said Erika Franklin Fowler, co-director of the Wesleyan Media Project. “Especially following several weeks of ad dominance by the opponent.”

Mr. Romney’s absence from the air made sense before the party’s convention in late August, since the campaign’s cash flow became so slow over the summer that it was forced to borrow $20 million to carry it through the event, when his formal nomination freed up tens of millions of dollars for the general election.

Yet at the same time Romney aides worked hard to project the image of a fund-raising machine far outpacing the president’s.

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Romney aides released informal dollar figures that lumped several pools of money — some available for his use, others not — into a single figure, providing a perception greater than reality: $106 million in June and $101 million in July, far more than Mr. Obama and the Democrats.

Yet those figures obscured the fact that most of the money Mr. Romney was raising was reserved for those other political entities like the Republican National Committee.

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And the party committee, which Mr. Romney helped propel to record-breaking receipts in July, is allowed to spend only about $22 million on advertising that is coordinated with Mr. Romney.

Even now, a large though unknown portion of Mr. Romney’s fund-raising is not going directly into his campaign account.

A closer look at Mr. Romney’s own filings revealed that Mr. Obama, while trailing in overall party fund-raising, was pulling far more money than Mr. Romney into his campaign account, the most useful and flexible dollars a candidate has to spend, in part because of strong collection from small donors who could give again and again without hitting federal limits.

Mr. Romney’s aides declined to discuss their advertising plans, saying that unlike the Obama campaign, which has reserved more than $40 million in time through Election Day, it will not telegraph its intentions for competitors to see.

As of the end of July, the Republican Party had an additional $15 million left to spend in coordination with Mr. Romney before it reaches its federal spending limits. And though no one knows the precise amounts, the Romney campaign will have millions at its disposal that it can drop into a television market at any given moment.

So far it is only buying several days or a week of advertising at a time, a sign that it is being extremely frugal. According to a review of spending figures provided by a group that tracks political advertising, from Sept. 10 through Sept. 24, Mr. Romney and his allies reserved $3.7 million in advertising time in Ohio. That compared with $5.2 million for Mr. Obama and his allies.

In Colorado, Mr. Romney is being outspent $2.2 million to $1.5 million during that same period. In New Hampshire, Mr. Obama is spending $1.2 million, compared with $380,000 to benefit Mr. Romney. The vast majority of that is coming not from the Romney campaign but from American Crossroads, the conservative super PAC.

Asked about the campaign’s budget on Wednesday, Spencer Zwick, Mr. Romney’s finance chairman, said simply, “We have spent our money smartly and efficiently.”