Enemy combatants, indefinitely detained. Warrantless searches. Allegations of torture. The War on Terror has spawned many questions about the interplay between security and personal liberties—questions that fall under the general heading of “national security law,” a field originated at the UVA School of Law 35 years ago and now taught at most American law schools.

Sadly, too many Americans on both sides of current policy debates remain ignorant about important aspects of this highly specialized field, and that contributes to our current national disunity. Some of the most criticized government programs in the War on Terror are fully consistent with legal norms, while others—defended by some able lawyers—can’t easily be reconciled with America’s legal obligations.

No serious expert believes al Qaeda terrorists are entitled to the full protections of the 1949 Geneva Convention Relative to the Treatment of Prisoners of War. Even if they were covered, they would have no right to legal counsel or a day in court. Under the Conventions, POWs may be detained without trial for the duration of hostilities. During World War II, we detained more than 400,000 Germans and Italians in POW camps across America—without access to lawyers or judicial hearings. Detainees who are charged with crimes are entitled to procedural safeguards to ensure a fair trial, but Article 84 provides they “shall be tried only by a military court.”

In my view, perhaps the most tragic blunder in the War on Terror has been the abuse of detainees. As the Supreme Court was handing down its Hamdan opinion last June, holding that Common Article 3 of the Geneva Conventions applies to the War on Terror, I was delivering a lecture at the Naval War College making precisely the same point. Common Article Three doesn’t just prohibit “torture”; it requires that all detainees be “treated humanely.” Material breaches of this obligation are war crimes.

I believe that the government has done a horrendous job of explaining the legal basis for the National Security Agency’s controversial terrorist surveillance program, which monitors communications by known and suspected al Qaeda terrorists abroad, even when they communicate with people inside this country. Former UVA government professor Quincy Wright observed in his 1922 classic, The Control of American Foreign Relations, “when the constitutional convention gave ‘executive power’ to the President” in Article II, Section 1, of the Constitution, “the foreign relations power was the essential element in the grant.” Jefferson explained in April 1790, “[t]he transaction of business with foreign nations is executive altogether”—a view shared by Washington, Madison, Chief Justice John Jay and Alexander Hamilton. In Marbury v. Madison (1803), Chief Justice Marshall used control over foreign affairs as an example of presidential constitutional discretion, adding “there exists, and can exist, no power to control that discretion.” And in the landmark 1936 Curtiss-Wright case, the court declared Congress was “powerless to invade” the president’s negotiation power as “sole organ of the nation in its external relations.”

This history is important, because it affects the debate about whether the current president is a lawbreaker. Put simply, the real issue is which political branch has been “breaking the law.” John Marshall declared in Marbury, “an act of the legislature repugnant to the Constitution is void.”

In 2002, the unanimous FISA Court of Review observed that every federal court that considered the issue held the president has inherent constitutional authority to conduct warrantless foreign intelligence searches, adding: “FISA could not encroach on the president’s constitutional power.”

There remains the issue of whether the NSA wiretap program violates the Fourth Amendment’s prohibition against “unreasonable searches and seizures.” Many have confidently asserted that every lawful search must be preceded by “probable cause” and a judicial warrant. But in Von Raab, the Supreme Court held in 1989 that “neither a warrant nor probable cause ... is an indispensable component of reasonableness in every circumstance.” Courts have consistently upheld the constitutionality of warrantless searches of commercial airline passengers and their luggage. As one eminent jurist reasoned: “When the risk is the jeopardy to hundreds of human lives and millions of dollars of property inherent in the pirating or blowing up of a large airplane, that danger alone meets the test of reasonableness.” Early last year, I testified twice before the Senate Judiciary Committee on the NSA program, and not one member of either party argued the wiretaps were “unreasonable” or should be stopped.

Courts and commentators will no doubt continue to struggle to find the proper balance between civil liberties and security in the War on Terror, but two things ought to be clear. First, to fully understand some of these issues, knowledge of national security law is critical. And secondly, if we err in our judgment and sacrifice the Bill of Rights on the altar of national security, Osama bin Laden will have won a far greater victory than was apparent in 2001 as we dug through the rubble of the World Trade Center.

UVA law professor Robert Turner co-founded UVA’s Center for National Security Law in 1981.