Sen. Richard Lugar’s concession speech -- coming, as it does, after years in which Lugar mostly buckled to the extreme elements in his party -- is more evidence of one of my personal laws of politics: Everything a politician says about American politics after they resign from office or lose in a primary is more interesting than anything they say while actually serving. Call it the Bayh rule.

Evan Bayh: An unremarkable senator, a great near-retiree, and a horribly disappointing ex-senator. (Spencer Platt/GETTY IMAGES)

Which was thoroughly surprising. Bayh had never shown much interest in process issues. He wasn’t a co-sponsor of the major campaign-finance reforms. He’d never authored a proposal to remake the filibuster. And yet here he was, unveiling a fully formed, genuinely radical plan to remake the institution he’d never evinced the slightest interest in changing. He’d gone, overnight, from a thoroughly unremarkable senator to a thoroughly remarkable near-retiree.

But Bayh’s retirement speech wasn’t the only classic of the genre. There was Olympia Snowe’s broadside, in which she leveled with the American people and said that “I do not realistically expect the partisanship of recent years in the Senate to change over the short term.” If it were up to me, that’s where discussions of how to “fix” Washington would start. Instead, it’s usually something they deny.

Nor is it just Republicans who give great resignation. When Rep. Barney Frank announced his retirement, he held a press conference in which he argued, that “the leverage you have within the government has substantially diminished. The anger in the country, the currents of opinion are such that the kind of inside work I have felt best at is not going to be as productive for the foreseeable future, and not until we make some changes.”

For Frank, a lion of the House who had recently chaired the powerful Financial Services Committee, to say that the “inside” game — which is to say, traditional legislating — is more or less dead was a remarkable admission. It’s also correct: From the Simpson-Bowles Committee to both Gangs of Six to the deficit-reduction “supercommittee,” the last few years have been marked by the near-continuous failures of backroom negotiations.

The truth is that if you stopped listening to serving members of Congress and instead talked only to the retirees and the losers, you’d have a much better idea of how Congress really works -- and what should be done about it.

Of course, the clear view of Congress’s failures that often accompanies retirement doesn’t always last very long. Take Bayh. After decrying the influence of money in politics and polarization on the Senate, he joined the lobbying firm McGuire Woods, the private-equity giant Apollo Management, and Fox News. “It’s as if he’s systematically ticking off every poison he identified in the body politic and rushing to dump more of it into the water supply,” I wrote.

On Twitter, The Atlantic’s Matt O’Brien helpfully closed the circle on this by proposing “The Bayh Corollary”: “The things [politicians] do after they retire are much worse than the things they say after they retire.” That seems right, too. We’ll see, in a year or two, whether Lugar manages to avoid it.