Mr. McCurdy said that there was “no shortage” of former members of Congress or high-level administration types interested in his soon-to-be vacant post, but that they were probably at a disadvantage.

And it is not just partisanship. Many politicians are not seen as having the skill set necessary for running large organizations. Senate and House offices are essentially small businesses, run very top-down, with a single goal — the re-election of the chief executive. Not to mention that politicians are often coddled with staff aides enthusiastically tending to their needs and frequently very reluctant to challenge them — or get an earful when they do. Association executives have to contend regularly with executives who are successful in their own right, with proven track records in their field.

“Even though politicians say they have a lot of bosses, they really don’t,” Mr. McCurdy said. “You have to understand it is a different role. You have to understand how to effectively work with boards, manage boards, lead boards, but also learn from and listen to boards.”

And while politicians get judged every two or six years at the ballot box, those running the associations say they are constantly evaluated.

“With how much politics has changed in the last 10 years and the continuing focus on the bottom line, every company in America is looking at their trade association and trying to figure out what value they are getting out of it,” said Mr. Sommers, who is overseeing an organization with a $230 million budget and 350 employees worldwide.

No doubt some Washington-based advocacy groups will always welcome a big-name former lawmaker with extensive contacts who is considered capable of bringing in members and drawing the attention of the news media. And to organizations with a strong ideological bent of their own, partisanship won’t be a problem. But given the turnover in Congress and potential losses by incumbents of both parties next month, there could soon be a glut on the market.

A few departing members such as Speaker Paul D. Ryan will be able to rake in substantial speaking fees — at least for a while. Others could catch on with lobbying and law firms to serve as strategic advisers while waiting for lobbying bans to expire. But the job market isn’t what it once was for ex-office holders, particularly those who weren’t committee chairmen or in leadership.