Sensing that the target audience has reached its limits, Representative Jim Renacci of Ohio has canceled $850,000 in advertisement reservations for the final days of his campaign for re-election, going dark on network television as one of the most expensive House races draws to a close.

The decision marks perhaps the most dramatic response to the relentless advertising wars in the first presidential campaign since the Supreme Court’s Citizens United decision opened the financing floodgates. As of Tuesday, the Cleveland media market has been pummeled with 73,178 political ads this year, according to Kantar Media, which tracks such ads. Mr. Renacci said advertising in that onslaught would be a waste of time and money, although he will maintain a small amount of commercials on cable channels.

“Quite frankly, as this election cycle moved forward, we noticed Ohio voters were really using their televisions for target practice,” he said in an interview. “And who can blame them?”

Democrats portrayed the move as an enormous political mistake in a campaign against another incumbent, the Democratic Representative Betty Sutton, in a redrawn district that is largely new to both of them. A senior aide to the Sutton campaign said Mr. Renacci was assuming every mind was already made up, even though in a race this close, only a few undecided voters could make a difference.

“Tom Ganley, Betty’s opponent two years ago, made the very same argument when he pulled down his ads. He went on to lose by 10 points,” said Steve Fought, a Sutton campaign spokesman.

But Mr. Renacci said he had been thinking of doing this all along. The campaign had reserved air time for the final two weeks but had gone up early in the summer and spent most of its advertising dollars in August, when the airwaves were not so saturated. He said he did not actually pull any ads, but he did cancel reserved slots.

The Sutton aide said Mr. Renacci’s advertising buyer informed networks of the decision Monday night.

“People are not paying attention. They are just turning it off,” Mr. Renacci said, relating his own experience of watching nine consecutive negative attack ads aired while he was watching a recent television show.

The Cleveland area is second only to Las Vegas in the number of political ads aired this year. Both cities are dealing with a close presidential contest, a hard-fought Senate campaign, close House races and an influx of advertising from outside groups.

Mr. Renacci said he most often hears the words “overwhelming” and “nauseating” from voters. He said it was Ms. Sutton who had miscalculated: She has run a more traditional campaign, husbanding her resources for a final ad blitz when voters in suburban Cleveland are either keeping the television off or taping their shows and fast-forwarding through the ads.