This would seem to make the case for obstruction under Article II ironclad. But the president’s lawyers have seized on a peculiarity of the House process in this case.

Buckner F. Melton Jr.: No wonder the impeachment trial is such a mess

Although the House investigation into Ukraine was initiated by three standing committees exercising their general oversight power and the subpoena power conferred on them by Rule X of the standing rules of the House, on September 24, Speaker Pelosi announced her support for an impeachment inquiry. But not until October 31 did the House as a whole approve a resolution formally declaring the ongoing investigations to be an impeachment inquiry and laying out the process for its public phase.

The president’s counsel argues that all the subpoenas issued by the Foreign Affairs, Intelligence, and Oversight Committees prior to October 31 were invalid because the House hadn’t formally adopted an impeachment resolution. Therefore, they say, the president had no obligation to comply with any of them, thus exonerating him from obstruction. That is, to be plain, ridiculous. The three House committees that began the investigation on September 9 indisputably had the constitutional authority to do so as part of the oversight power. And they had the express authorization to issue subpoenas under House rules. The president’s position, incredibly, is that if an ongoing oversight investigation begins to produce evidence that might result in impeachment, the committees conducting that investigation somehow lose their subpoena authority until the whole House declares a formal impeachment inquiry.

This is, not to put too fine a point on it, absolutely daft. The power of the House to compel presidential disclosure increases once impeachment is contemplated. Some have argued that this increment of constitutional authority is not available unless and until the House formally declares that it is engaging in an impeachment inquiry, a point I have refuted elsewhere. But the White House is now arguing that the ordinary investigative powers of Congress disappear as soon as it becomes evident to House leadership that impeachment should be contemplated.

Not only is this view unfounded in the Constitution, but it would create an absurd catch-22. It is certainly right that the House should not convene a formal impeachment inquiry unless there is substantial evidence upon which to premise so grave a step. But except in a case where the matter at issue has already been investigated by the Senate or outside agencies (as was true with Richard Nixon and Bill Clinton), the only way to get such information is for the House to demand it under its general oversight authority. Trump is saying that, with respect to any subject on which the House might find the president impeachable, he can issue a blanket order to the entire executive branch blocking access to information unless and until the House passes a formal impeachment-inquiry resolution. As long as he can enforce compliance with that order, the House will not get such information … and the result is checkmate.