Political hypocrisy is so pervasive that it calls to mind Gregg Allman’s objection to the term “Southern rock.” The one has so much to do with the other, Allman said, that one might as well say, “rock rock.” To many voters, the seeming lack of ideological consistency in our elected officials smacks of corruption.

But hypocrisy, suggests recently retired Representative Barney Frank, is less evidence of corruption than evidence of its absence. It is what makes Congress function. It is the only tool legislators have after they’ve rooted out real corruption.

“Legislators do not pay each other for votes, and every member of a parliament in a democratic society is legally equal to every member,” Frank writes in his new memoir, Frank: A Life in Politics From the Great Society to Same-Sex Marriage. For legislators, cooperation is a form of political currency. They act in concert with other legislators, even at the expense of their own beliefs, in order to bank capital or settle accounts: “Because parliamentary bodies have to arrive at binding decisions on the full range of human activity in an atmosphere lacking the structure provided by either money or hierarchy, members have to find ways to bring some order out of what could be chaos,” Frank writes. So trading votes is how the business of politics is conducted. “Once you have promised another member that you will do something—vote a certain way, sponsor a particular bill, or conduct a hearing—you are committed to do it.”

In other words, constituents might not find their representative’s vote on an environmental bill to be consistent with their ideology, or might think that their senator’s take on the filibuster is dependent almost entirely on which party is in the majority—and they’re probably right. What Frank is revealing is that elected officials understand their votes in the same way, but that there’s no shame in that. As Frank has it, legislators have to act in ideologically inconsistent ways in the short run if they want to advance their larger objectives in the long run, as those larger objectives can only be achieved with teamwork. And the other members of their legislative team are only going to play ball with them if they know that they’ll take one for the team, that they’ll vote for something they don’t like because the team needs it.

And Frank goes further: Instead of seeing political flip-flopping as a necessary evil, he suggests it is inherent to democracy. In an interview for the TV show I host on The Jewish Channel, Up Close, he explained that, “Any legislator is in an essentially compromised position, given the nature of democracy, because your decision about how to vote inevitably is a compromise—our system wouldn’t work otherwise—between your own views and your voters’.” Frank argues that observing a legislator in any single moment or vote can give a false perspective on that legislator. Votes cast in support of apparently contradictory measures on several different occasions offer a more accurate view of a particular representative than any single vote held up to exemplify their approach to legislating.

As legislators are pulled this way and that by public opinion and by their commitments to fellow legislators, there’s also another force at play: the passage of time. Legislatures have a “strong bias against relitigating an issue that has been legitimately decided,” Frank writes. So legislators are left to choose among the available options at the time of the initial vote, and then often unable to revisit the issue later, even as opinions shift. “If every issue is always on the active agenda, if an issue that was already disposed of by a majority can be reopened whenever the side that lost regains and advantage, instability infects not just the body that made that decision but also the society that it is governed by.”

This is how Frank, the first gay member of Congress to come out voluntarily, ended up as an early architect of the policy that would eventually become “Don’t Ask, Don’t Tell.” To head off the prospect of gays being entirely banned from the military in 1993, Frank advocated a middle path that he felt was the best achievable result at the time. Even though Bill Clinton ultimately took the plan in a harsher direction than Frank had hoped for, Frank knew he couldn’t introduce a bill to remove it at every subsequent congressional session. But choosing not to revisit “Don’t Ask, Don’t Tell” at every opportunity didn’t say anything about his desire to see it end, in the same way that the initial proposal didn’t say anything about his desire to see gays serve openly in the military.

Frank’s view of hypocrisy is a self-serving narrative, to be sure, but it’s also a very rare example of a legislator choosing to actually explain such behavior, rather than pretending that such behavior does not exist.

But there are two parts to Frank’s theory that would nonetheless drive the average political observer bananas. If you have any faith left in our political system as an authentic representation of voters’ beliefs, you might want to skip the next two paragraphs.

If there’s any blame to be doled out in connection with political hypocrisy, Frank implies, it’s to be placed on the heads of voters who criticize legislators for it, instead of accepting it as a necessary part of democratic politics. “Legislators who accommodate voter sentiment are denounced as cowardly, and those who defy it are just as fiercely accused of rejecting democratic norms,” he writes. And while “both of these opposing views of a representative’s obligations are wholly defensible,” something “less” defensible to Frank is “the tendency of most voters to alternate between them, depending entirely on whether or not they agree with the official’s substantive position.”

And then there’s the knockout blow for any political idealist. Frank reveals that in the special economy of Congress, believing that voting a certain way on a bill is wrong is the worst reason one can cite for going against the tide. Once one is committed to voting a certain way, one can ask to be “released” from that obligation “if you can plausibly plead some unforeseen change in circumstances, and the convention is for that colleague to do so if your reason is good enough.” But what counts as a good enough reason? “Usually political necessity,” Frank writes. Indeed, he adds in a passage about former President Ronald Reagan’s proposed 1982 budget cuts, “In a partisan political system, pleas of political self-interest outrank a claim to know better than one’s party colleagues what is best for the country.” Privileging partisanship over personal beliefs, Congress rewards those who look past the strength of the available evidence or the depth of their own convictions, choosing instead to vote to accrue credit or pay political debts.

If you want to survive in Congress, you can toss your well-thumbed copy of German modernist philosopher Immanuel Kant’s Grounding for the Metaphysics of Morals out the window. Kant’s notion of a “categorical imperative,” in which one does what is right without compromise, directly contradicts Frank’s defense of legislating. In Kant’s ideal world, we wouldn’t have anything as craven as legislative half-measures leading toward eventual recognition of certain minorities’ rights. In the Congress that Frank describes, it’s all quite a bit messier, and moral interests must be subdued to practical and political ones if there is any hope for progress at all.

But before political true-believers decide to use Frank’s revelations as reason to march on Capitol Hill with torches and pitchforks in hand, they should consider that voters act just like the representatives they elect. Frank’s take is largely consistent with empirical research on voters’ political biases. A draft study from Eric Posner and Cass Sunstein published in January surveyed a series of groups of approximately 200 people about their political biases, and found that they tend to think about relationships first, and beliefs second. Ask people if they think former President George W. Bush “did the right thing” in using recess appointments, and a majority of Republicans say “yes,” while 68 percent of Democrats say “no.” Ask an identical question, but swap out Bush’s name for that of President Barack Obama, and 89 percent of Republicans will oppose Obama’s approach, while 66 percent of Democrats will support it.

What’s more, Posner and Sunstein found that political biases even influence our thinking as to whether something is possible. Asked both whether they supported or opposed same-sex marriage, and whether Congress could ban same-sex marriage, respondents showed their ideological bias coloring their view of Congress’s powers: “Among same-sex marriage supporters, only 10 percent believed that Congress could ban it; 90 percent believed that Congress could not ban it. Among opponents, 49 percent believed that Congress could ban same-sex marriage; 51 percent believed that Congress could not ban it.”

And yet, Posner’s and Sunstein’s study still revealed a gap between politics and ideology. These numbers, after all, don’t show precisely opposite views in play: only some respondents switched sides on an issue when the political players changed, and a majority of those who opposed same-sex marriage nonetheless agreed with their political opponents that Congress could not ban it. These gaps reveal that deep down, there are ideological lines that many people won’t cross, no matter the dealmaking, partisanship, or personal incentives involved.

Frank recognizes this, too. In our interview, he spoke about the back-and-forth between ideology and politics as “this constant thing,” and suggested that we all need to find answers to it. For Frank, it starts with representing those who elected him: “I will run for office and I will tell you what I think, and then I will go ahead and do what I think right, and if you don’t like what I’m doing, then you can kick me out.” But in practice, voters provide inherently conflicted guidance—and sometimes legislators may conclude that voters are simply wrong. Frank’s answer to this dilemma is to prioritize based on a moral hierarchy he’s constructed: “There were several issues that I thought were very important—moral issues,” and these were not open for debate. However, “There were some issues which were less important to me—where the roads should go; I would listen to my voters on those things.”

Posner and Sunstein recognize this gap, as well. “A key precondition of flip-flopping thus seems to be ambiguity as to whether a constitutional or institutional norm exists,” they write. In other words, the flip-flopping gap voters create—between what they think in a vacuum and what they think when partisanship is mixed in—exists because of a gap in law or custom. Posner and Sunstein think we can close some of that gap with new approaches: introducing a veil of ignorance into certain decision-making by removing partisan markers from policy proposals, for example, or increasing the number of public officials who are career professionals not appointed by politicians. But of course, though the gap can be narrowed, it can never be fully closed.

At some point, after all, norms and laws leave people without clear guidance on specific issues, in the same way that elections and political coalitions do. At these times, voters and elected officials are driven by a variety of competing interests, and whatever approach wins out is likely to leave someone pointing a finger with accusations of hypocrisy. And, to a degree, the accusers will almost always be right that hypocrisy wins the day. The best we can do is be frank about it.