Choosing his words carefully, George W. Bush all but accused critics of his extralegal warrantless wiretaps of giving aid and comfort to Al Qaeda: “It was a shameful act, for someone to disclose this very important program in time of war. The fact that we’re discussing this program is helping the enemy.” If so, the ranks of the treasonous now include leaders of the President’s own party, and the New York Times‘s revelations of illegal wiretaps foretell an earthquake. Senator Lindsey Graham, last seen carrying gallons of water for the White House on the status of Guantánamo prisoners, will have nothing of Bush’s end run around the Foreign Intelligence Surveillance Act: “Even in a time of war, you have to follow the process,” he said flatly. An infuriated Arlen Specter, Senate Judiciary chairman, whose good will the White House depends on in the upcoming Supreme Court confirmation of Samuel Alito, declared the President’s domestic spying “inexcusable…clearly and categorically wrong” and plans hearings.

For the generations who came of age after the mid-1970s, it is worth recalling why warrantless domestic surveillance so shocks the political system. It needs to be repeated that the same arguments cited by Bush–inherent presidential power and national security–sustained the wiretapping of Martin Luther King Jr., unleashed illegal CIA domestic spying and generated FBI files on thousands of American dissidents. It needs to be repeated that in 1974, the articles of impeachment against Richard Nixon included abuse of presidential power based on warrantless wiretaps and illegal surveillance. It needs to be repeated that a few months later, presidential aides named Cheney and Rumsfeld labored mightily to secure President Ford’s veto of the Freedom of Information Act, in an unsuccessful attempt to turn back post-Watergate restrictions on homegrown spying and government secrecy.

Most of all it needs to be repeated that no constitutional clause gives the President “because I said so” authority. The fact that former Deputy Assistant Attorney General John Yoo tried to concoct a laughable fig leaf out of Congress’s 9/11 use-of-force resolution in no way diminishes the President’s culpability. Nor does the evident collusion of a handful of Senate leaders, including minority leader Harry Reid, who was evidently informed at least partly about the spying program.

A belligerent President vowed that warrantless domestic spying will continue, whatever the letter of the Foreign Intelligence Surveillance Act or the Bill of Rights. Bush also none too subtly threw down the gauntlet to Congress: “An open debate about law would say to the enemy here’s what we’re going to do.” But open debate is the very essence of democracy; without it, there is little to prevent a slide into authoritarianism (indeed, the ACLU has released FBI documents that indicate the bureau has expanded the definition of “domestic terrorism” to include citizens engaged in nonviolent protest and civil disobedience). Congress therefore has a solemn obligation to carry out a full investigation into these grave breaches of our constitutional liberties.

Where will the revelations end? Given Bush’s repeated depiction of leakers and critics as aiding the enemy, is it a paranoid fantasy to imagine a secret-wiretap list extending to reporters and government officials? And given the palpable outrage among Republicans as well as Democrats at the President’s contempt for basic constitutional law, is it impossible to imagine illegal wiretaps leading to the final undoing of the Bush presidency?