It’s easy to get mired in the technological complexities of the president’s Terrorist Surveillance Program. Essentially, the program inaugurated warrantless electronic monitoring of international phone calls and e‑mails — even those that originate or terminate inside the United States. Secretly implemented in 2001 but unearthed and publicized four years later by the New York Times, the program was expanded by Congress in the August 2007 Protect America Act.

The act was scheduled to expire on Feb. 1, but it was extended for 15 days — until Friday — while the House and Senate thrash out competing bills to keep the program alive.

Congress and the White House are finally negotiating, after grappling with this threshold constitutional question: Who gets to decide whether the program strikes the right balance between civil liberties and national security — that is, whether it violates the Fourth Amendment’s ban on “unreasonable” searches?

The Bush administration’s position had been consistent and uncompromising. Former Attorney General Alberto Gonzales put it this way: Article II of the Constitution says, “The executive power shall be vested in a president” who “shall be commander in chief” of the armed forces. That power, argued Gonzales, trumps any congressional action during time of war.

Presumably, if wartime security interests are implicated, the president can unilaterally authorize wiretaps of Americans anywhere, indefinite detention of U.S. citizens, library records searches, national security letters, secret CIA prisons, “enemy combatant” declarations, military tribunals and interrogation techniques that may have violated our treaty commitments.

Not so, said Justice Robert Jackson, concurring in Youngstown Sheet & Tube vs. Sawyer —the 1952 Supreme Court case denying President Harry Truman’s authority to seize the steel mills. First, wrote Jackson, when the president acts pursuant to an authorization from Congress, “his authority is at its maximum.” Second, when Congress has neither granted nor denied authority, “there is a zone of twilight in which (the president) and Congress may have concurrent authority, or in which its distribution is uncertain.” But third, where the president takes measures incompatible with the express or implied will of Congress, “his power is at its lowest.”

The secret Terrorist Surveillance Program fell in the third category: The president acted in the face of an express statutory prohibition in the Foreign Intelligence Surveillance Act. Most presidents, when they think a law is outdated or ineffective or otherwise ill advised, ask Congress to amend or repeal the law. President Bush took a shortcut: He attempted for years to repeal FISA by himself by ignoring its provisions.

Recently, in a series of decisions — Hamdi vs. Rumsfeld (2004), Rasul vs. Bush (2004) and Hamdan vs. Rumsfeld (2006) — the Supreme Court has again rejected the notion that the executive may do pretty much as it pleases in wartime, regardless of congressional input. As a result, the Bush administration was dragged kicking and screaming into seeking authorization from Congress — for the Detainee Treatment Act (2005), Military Commissions Act (2006), the Protect America Act (2007) and now two pending bills to reautho rize the Terrorist Surveillance Program (the RESTORE Act in the House and the FISA Amendments Act in the Senate).

Perhaps Congress will make the wrong policy choices as it reconsiders the program. If so, a constitutional challenge from one or more civil liberties groups is highly likely. But misguided policy judgments by Congress will be difficult to challenge on constitutional grounds under the rubric contained in the Youngstown court decision. After all, the president’s authority is “at its maximum” when he acts with express congressional authorization.

What that means, of course, is that abiding by the Constitution will not always shield us from bad laws. Nonetheless, even if the Constitution is not a sufficient guidepost, it is certainly a necessary guidepost.

For many years, we were at risk of losing important civil liberties through unchecked transgressions by the executive branch. Maybe we are still at risk. But thanks to the media, the courts and — belatedly — an energized opposition in Congress, the administration has finally resigned itself to a semblance of congressional oversight, even if judicial scrutiny remains inadequate.

The president’s bogus claims of limitless executive power are, for now, on hold. That’s the right constitutional precedent even if it ultimately produces the wrong policy outcomes. Longer term, the precedent is more important than temporal policy judgments. Justice Sandra Day O’Connor’s plurality opinion in the Hamdi case nicely captured the key principle: “Whatever power the U.S. Constitution envisions for the Executive … in time of conflict, it most assuredly envisions a role for all three branches of government when individual civil liberties are at stake.”