The intensity of that campaign left a mark on Ms. Pryce, who said she was turned off by the vitriol as well as the more than $4.5 million she had to raise and pour into her own attack ads. “It was obscene the amount of money I had to spend,” said Ms. Pryce, a former municipal court judge.

Ms. Pryce said that after adopting her daughter as an infant, she knew she would have to leave Congress at some point and had considered retiring before the 2006 election. But she hesitated and then felt compelled to stay and defend her seat once she drew a credible challenger. Yet Ms. Pryce said she continued to be torn between Congress and her family — she was still wincing a few days ago about forgetting pajama day at her daughter’s kindergarten — and around the Fourth of July decided to step down.

“Being in the minority makes it easier,” she said, “but I was going in that direction anyway.”

Ms. Pryce, thoroughly familiar with the rough and tumble of modern politics, sees little hope of a shift in tactics unless there is a public backlash, since she said her last campaign convinced her that negative ads work.

“I don’t think anything will change until Americans revolt and get it into their heads that they need to be informed voters instead of just listening to the paid political ads,” she said.

Mr. Hobson, too, had considered leaving in the past and in anticipation sold his condominium in the Washington area a few years ago. But as chairman of the appropriations panel that distributes money for energy and water projects, he was in a position to benefit his state. Now, at 71, he said he wanted to leave office while he was in good health. The death earlier this year of a friend, Representative Paul E. Gillmor, is not far from his mind, he said.

Unlike the other two Ohio districts, Mr. Hobson’s district in the Springfield area is probably secure for Republicans. And he has been grooming a successor. He also has a reputation for bipartisanship in Congress, traveling on official trips with Speaker Nancy Pelosi, Democrat of California, and cutting spending deals across the aisle.

“The Democrats and I have gotten along very well,” Mr. Hobson said. “I may have gotten more money with them than I did under our guys.”