Here’s one thing President Obama and Speaker Boehner agree on: they don’t want you to know what happened at their meeting Sunday about taxes and spending. “We’re not reading out details of the conversation,” said identical statements issued by the White House and the Speaker’s office.

It’s quite a stance from two politicians who profess commitments to open and transparent government.

Mr. Obama, for example, issued a memo early in his administration asserting, “My Administration is committed to creating an unprecedented level of openness in Government…. Government should be transparent. Transparency promotes accountability and provides information for citizens about what their Government is doing…. Government should be participatory. Public engagement enhances the Government’s effectiveness and improves the quality of its decisions. Knowledge is widely dispersed in society, and public officials benefit from having access to that dispersed knowledge.”

And Mr. Boehner, in his pre-election 2010 “Pledge to America,” said “Americans have lost trust with their government…Backroom deals, phantom amendments, and bills that go unread before being forced through Congress have become business as usual. Never before has the need for a new approach to governing been more apparent …We cannot continue to operate like this….We will ensure that bills are debated and discussed in the public square by publishing the text online for at least three days before coming up for a vote in the House of Representatives. …Legislation should be understood by all interested parties before it is voted on.”

Mr. Boehner’s pledge said “we are fighting to bring much-needed sunlight to the process…we will end the practice of packaging unpopular bills with ‘must pass’ legislation to circumvent the will of the American people. Instead we will advance major legislation one issue at a time.”

Got that? Mr. Boehner’s for “sunlight” and against “backroom deals,” and Mr. Obama’s for “an unprecedented level of openness.” Yet neither one of them will tell the American people what they said at the meeting they just had about the federal budget. Mr. Boehner might want to refer to that earlier statement about how “Americans have lost trust with their government,” and consider whether this sort of behavior is among the causes.

As a matter of history, not all departures from open government have ended badly. Before Samuel Adams told the Massachusetts House of Representatives about Governor Thomas Hutchinson’s letters to an aide to George III’s prime minister misrepresenting the situation in Massachusetts, the public galleries of the house were cleared. The Philadelphia convention that drafted the U.S. Constitution met in secret.

But even secrecy has its limits. After the Constitution was drafted, after all, it was available for lengthy public debate and discussion in forums like the state ratifying conventions and the Federalist Papers. Whatever tax and spending deal Mr. Obama and Mr. Boehner reach isn’t exactly of Constitutional import, but it can nonetheless benefit from being subject to public discussion before being rushed to passage. Yet because of the ticking clock between now and the end of the year, not to mention the holiday calendar, it’s quite possible that a deal will be rushed through before it’s adequately considered.

The president of Americans for Tax Reform, Grover Norquist, gets a lot of attention for the pledge that his group gets congressmen to sign opposing tax increases. The Norquist position of the moment that may be even more consequential than the pledge is his call for a C-Span camera in the room with President Obama and Speaker Boehner for the budget negotiations, and for his suggestion that “The final agreement must be put in writing, in actual legislative, legal wording and placed online for every American to read for seven full days.”

If Mr. Boehner and the House Republicans break their no-tax pledge and also break their no-back-room-deal pledge, there will be a tendency to focus on the tax side of it as the substance and to write off the back-room-deal part of it as mere process. But the two are closely related. First of all, if a politician is a promise-breaker on one issue, he is likely to be on other issues, too. But second, it’s the public pressure that’s likely to keep the politicians in line when it comes to the substance.

If Messrs. Obama and Boehner really think that the only way they can get a deal is to keep it secret from the American people, then the consistent step for them would be to retract all that high-minded prose about “public engagement” and “the will of the American people.” They could replace it with something more accurate, which is that they don’t want the American people really to know what they are up to until it’s too late to stop it.

Mr. Stoll is editor of FutureOfCapitalism.com.