The recent revelation that the National Security Agency has secretly been collecting phone-call data from millions of Americans comes on the heels of Attorney General Alberto Gonzales’ suggestion that the president might have ”inherent executive authority” to wiretap Americans’ domestic calls without a warrant. That was the latest in a series of extraordinary constitutional claims the Bush administration has made during the war on terror.

Among those claims: the authority to lock up American citizens on American soil and hold them without charges or trial for the duration of the war on terror and the power to bypass validly enacted statutes that interfere with any tactics the president wants to pursue in the war on terror. Behind all of these claims lies a common principle: Presidential power must be left unrestrained, checked only by the good faith of the executive and the remote possibility of impeachment.

What’s surprising is that even as the president has been hemorrhaging conservative support on issues such as immigration and spending, conservatives continue to back the president’s dubious constitutional claims. The right has long celebrated Hamiltonian ”energy in the executive,” but the president’s broad theory of executive power goes far beyond that. It borders on James Madison’s nightmare, in which legislative, executive, and judicial powers are concentrated in the same hands — a state Madison termed ”the very definition of tyranny.”

Nonetheless, leading conservatives react scornfully to any attempts to cabin Bush’s power. In March, observing Congress’s halting attempts to restore oversight to executive branch surveillance, the Wall Street Journal’s editorialists wrote: ”Let’s hope that the next time some Beltway potentate bemoans the ‘Imperial Presidency,’ everyone starts hooting with laughter. What we’re watching this week is the Lilliputians on Capitol Hill tying down a Bush administration that increasingly looks like Gulliver.”

A month later, Gulliver’s attorney general, testifying before Congress, advanced the administration’s theory of inherent executive authority to conduct warrantless surveillance of Americans’ domestic phone calls, while refusing to confirm or deny the existence of any such program. That day, the Justice Department issued what might be termed a ”nonclarification clarification” of Gonzales’s testimony: ”The attorney general’s comments today should not be interpreted to suggest the existence or nonexistence of a domestic program.”

Conservatives trust Bush not to abuse the vast powers he claims. But a few years ago, they recognized that not every president was worthy of unconditional trust. They recognized that the presidency can be captured by exceptionally venal, corrupt men who would stop at nothing to retain power. Fairly or unfairly, they saw President Clinton as such a man and denounced him in lurid terms.

Conservatives, including the Journal’s editorialists, railed against misuse of hundreds of FBI files and the alleged abuses of FBI powers during the Travelgate scandal. Even now with another candidate named Clinton leading the polls for the Democratic nomination, they unhesitatingly embrace theories of executive power that would allow any future president to spy on Americans without oversight and lock them up without trial.

At the annual meeting of the Conservative Political Action Committee back in February, former congressman Bob Barr, a hard-core conservative and a former impeachment manager in the effort to remove President Clinton, got a notably cool reception when he warned about the dangers of an increasingly imperial presidency. His opponent in the debate, Viet Dinh, the architect of the PATRIOT Act, was more of a crowd-pleaser. Dinh told the audience, ”The conservative movement has a healthy skepticism of governmental power, but at times, unfortunately, that healthy skepticism needs to yield.”

”At times” might more accurately be recast as ”from now on.” The Pentagon has taken to calling the fight against terrorism ”The Long War.” Unlike other wars, this one will not end with a peace treaty across a diplomat’s table. It will take decades, and when victory is achieved, we might not know with any certainty that we’ve won. The extra constitutional powers we tolerate now will be available for all future presidents, scrupulous or otherwise. Our entire constitutional system repudiates the notion that electing good men is a sufficient check on abuse of power. To preserve that system, this country sorely needs a resurgence of conservatives’ ”healthy skepticism.”