President Bush’s nominee for attorney general, Michael Mukasey, was asked an important question about Congress’s power at his confirmation hearing. If witnesses claim executive privilege and refuse to respond to Congressional subpoenas in the United States attorneys scandal — as Karl Rove and Harriet Miers have done — and Congress holds them in contempt, would his Justice Department refer the matter to a grand jury for criminal prosecution, as federal law requires?

Mr. Mukasey suggested the answer would be no. That was hardly his only slap-down of Congress. He made the startling claim that a president can defy laws if he or she is acting within the authority “to defend the country.” That is a mighty large exception to the rule that Congress’s laws are supreme.

The founders wanted the “people’s branch” to be strong, but the Bush administration has usurped a frightening number of Congress’s powers — with very little resistance. The question is whether members of Congress of both parties will do anything about it.

Congress is often described as one of three coequal branches, but that is not entirely true. As Akhil Reed Amar, a Yale law professor, observed in “America’s Constitution: a Biography,” Article I actually makes Congress “first among equals, with wide power to structure the second-mentioned executive and third-mentioned judicial branches.”