03/25/2013 11:37 am ET Updated May 25, 2013

Rand Paul Is Right

We like to say our nation has a system of laws, not men. But where do those laws end? Does the Constitution apply everywhere, or just in the United States? This question has suddenly vaulted to prominence thanks to an unlikely protagonist: Senator Rand Paul.

In his recent revival of the old-fashioned filibuster -- that is, one involving actual talking -- Sen. Paul harangued the Obama administration over its use of drones to kill American citizens abroad. And, more chillingly perhaps, he raised the specter of drone-fired missiles raining down on Americans at home.

Last week in the Washington Post, noted conservative columnist Charles Krauthammer declared that the targeted killing of an American by a U.S. drone was "inconceivable." At least when the victim remained on American soil. Yet "outside American soil," wrote Krauthammer, "the Constitution does not rule, no matter how much Paul would like it to."

This Paul vs Krauthammer smackdown highlights a question that has vexed American law since our founding. Exactly where do the Constitution's powers end? Is it a set of rules and rights governing all Americans, wherever they may be? Or is it instead a constitution for a particular place -- one that has clear and demarcated borders?

For much of American history, the Krauthammer view prevailed. The Constitution was thought to have little or no reach outside American borders. Even what "outside" meant was unclear, since federal territories -- such as California before statehood -- were sometimes thought to fall outside some constitutional rules.

What this all meant eventually became the subject of heated debate. Indeed, the presidential election of 1900 turned on this issue.

On one side was William McKinley; on the other, William Jennings Bryan. The burning question: "Does the Constitution follow the flag?" This question was significant because the U.S. had, by virtue of victory in the Spanish-American War, just acquired the Philippines and Puerto Rico.

But were these offshore islands even part of the U.S.? And did the Constitution apply in these islands? Did Filipinos, in other words, have full constitutional rights?

McKinley said no. Bryan said yes. The Supreme Court waited. Then, with the election results in, and McKinley president, the answer was clear. Or maybe it wasn't. The Court's rulings -- which were awaited by huge throngs around the nation -- were confusing and convoluted. Some parts of the Constitution did apply to these new American islands, the Court said. Yet others did not, since they were federal territories that were not likely to ever become states.

The great statesman Elihu Root, then Secretary of War, got to the heart of the matter. "Near as I can make out," he quipped, "the Constitution follows the flag -- but doesn't quite catch up with it."

This standard, if you can call it that, prevailed for several decades. Meanwhile, American courts in places like Shanghai -- yes, we once had a federal court in Shanghai -- did not recognize the full panoply of constitutional rights. Since the Constitution only partly ruled in our colonies, it plainly didn't rule at all in foreign nations.

Eventually, the Supreme Court rethought this position. In 1957 the nation was in war again, only this time it was a cold war that entailed a massive and historically-unprecedented overseas deployment of troops. And these troops brought their families to live in bases in places like Germany, Japan, and Korea.

When two of the wives of these servicemembers murdered their husbands -- one with an ax, after which she crawled into bed with his bloody corpse -- the Pentagon followed its usual practice and tried the wives by court martial. After all, the murders and the trials occurred outside American soil, and so there was no constitutional barrier to putting civilians before military judges.

The wives argued otherwise. And the Supreme Court agreed. Americans, decided the Court, do not check their rights at the jetway door:

At the beginning we reject the idea that when the United States acts against citizens abroad it can do so free of the Bill of Rights... when the government reaches out to punish a citizen who is abroad, the shield which the Bill of Rights and other parts of the Constitution provide to protect his life and liberty should not be stripped away just because he happens to be in another land.

In short, Rand Paul is right and Charles Krauthammer is wrong. The Constitution does apply to Americans abroad. And this has significance beyond an internecine GOP feud.

The Obama administration claims that it can kill Americans who actively participate in al Qaeda activities above a certain threshold, as long as capture is infeasible and some other standards, involving imminent threats and the like, are met. These limitations on the power of the president to order the death of a citizen exist because the Constitution binds the president everywhere.

Some six million Americans reside abroad. And our government is uniquely capable of projecting its power around the world. We ought to remember and be thankful, as Rand Paul has reminded us, that the Constitution reins in that power -- wherever we are.