It’s almost a relief, in a way, to hear Vice President Cheney’s office explain that he’s not bound by classified material rules covering the executive branch because he’s partly a legislator.

Considering what’s come out of that office lately, the vice president might have declared firmly that he was partly a parakeet.

In a secure and undisclosed birdcage.

There’s a reason, of course, why people suspect the vice president has, so to speak, flown off from the planet where the rest of us live. Last week, his office explained that it wasn’t bound by executive branch rules on handling classified materials because he is not “an entity within the executive branch.”

Cheney’s office declared that because presiding over the Senate is the only duty specified for the vice president in the Constitution – it’s always encouraging to see the vice president thinking about the Constitution – he’s actually in the legislative branch.

Or rather, in the opinion of his counsel, he is something unique, neither executive nor legislative, bound by the rules of neither – the vice president as constitutional platypus.

This came out of an inquiry by the Information Security Oversight Office, an office in the National Archives charged with overseeing the management of classified documents in the executive branch, about why it was getting no response from the office of the vice president. Actually, it’s not entirely true that it was getting no response; after the inquiry the vice president apparently tried to have the Information Security Oversight Office abolished.

Again, that’s almost a measured reaction; Cheney might have insisted that as vice president, he had the power to have National Archives employees tortured.

Still, the vice president’s insistence that he is untouchable because he is legislative and not executive sounded strange. As Dana Milbank noted in The Washington Post, when Congress asked about Cheney’s energy task force in 2001, he responded firmly that the probe “would unconstitutionally interfere with the functioning of the executive branch.”

Maybe he has a phone booth that he leaps in and out of to change constitutional identities.

Or maybe he just changes uncontrollably when the moon is full, or when Congress is in recess.

It’s hard to believe that the vice president really has a deep sense of himself as a legislator. On one of his relatively rare visits to the Senate floor, Cheney told Sen. Patrick Leahy, D-Vt., to perform an act which is not only anatomically difficult, but a clear violation of senatorial courtesy.

And over the past six years, that’s been one of Cheney’s friendlier gestures toward Congress, which he has tried constantly to ignore, minimize and generally shove out of the way of the executive branch. He has insisted that the White House has the authority to dismiss Congress on everything from the War Crimes Act to oversight investigations.

Who knew that the vice president considered himself partly congressional?

Well, it turns out that the people in Congress didn’t know. Stirred by his efforts to dodge legislative oversight by claiming executive privilege and evade executive oversight by declaring legislative identity, they have some questions. Noting the funding in the executive branch budget for a vice president who says he’s legislative, Democrats say the appropriations process might be used to check the vice president’s constitutional ID.

As House Majority Leader Steny Hoyer, D-Md., suggests, “We shouldn’t fund him in both branches.”

Or, as House Oversight Committee Chairman Henry Waxman, D-Calif., wrote to the vice president – straying, for a congressman, dangerously close to issues of metaphysics – “Is the official position of the Office of the Vice President that your office exists in neither the executive nor the legislative branch of government?”

Still, it’s possible that the vice president really does think, deep down, that he’s part of the legislative branch. After all, if Cheney believed that we knew where the weapons of mass destruction were, that U.S. troops would be greeted in Iraq as liberators, and that two years ago the insurgency was in its last throes, he might really believe that he’s basically a legislator.

Or maybe a velociraptor.