Editor's Note: This column is reprinted with permission of the Washington Examiner. Click here to read it at that site.

Last Thursday—which happened to be the 220th anniversary of the ratification of the Bill of Rights—the Senate passed a defense bill that demonstrates just how cavalier Congress can be with our fundamental liberties.

Given the opportunity to clarify existing law and confirm that American citizens are not subject to indefinite military detention at the order of the president—Congress punted.

After a debate in which key members seriously contemplated empowering the president to "Gitmo-ize" Americans suspected of terrorist activity, the National Defense Authorization Act of 2012 leaves the question open. Maybe he can, maybe he can't, so let's let the courts sort it out.

The legislation is ready for President Obama's signature, the president having caved on his earlier veto threat. Happy Bill of Rights Day!

It could have been even worse. An earlier version of the bill would, according to one of its cosponsors, Sen. John McCain, R-Ariz., have allowed the president to use the U.S. military to seize American citizens on the home front and ship them to Guantanamo.

Sen. Lindsey Graham, R-S.C., cheered the provision, because it would "basically say in law for the first time that the homeland is part of the battlefield." He added that "I believe our military should be deeply involved in fighting these guys at home."

James Madison, the father of the Bill of Rights, was somewhat less giddy about the prospect of militarizing the home front. "A standing military force, with an overgrown Executive will not long be safe companions to liberty," he warned at the Constitutional Convention, "the means of defense against foreign danger have always been the instruments of tyranny at home."

Yet for all the Tea Party-inspired Constitution-waving on the Hill, only a minority of Republicans seem to share the Founders' justified fear of standing armies at home.

An amendment that would have explicitly excluded U.S. citizens from the bill's military detention provisions failed by a 45-55 vote in the Senate, with only a handful of Tea Party Republicans—including Sens. Rand Paul, R-Ky., Mike Lee, R-Utah, and Mark Kirk, R-Ill.,—breaking with their party to oppose selective martial law within the United States.

The language that passed Thursday ducks the issue, stating that the bill isn't intended to change existing law on U.S. citizens arrested in the U.S. But the compromise Congress settled on settles nothing. Existing law is unclear, and the NDAA makes it murkier still.

In 2002 during the Bush administration, federal officials seized Brooklyn-born al Qaeda suspect Jose Padilla, declared him an "enemy combatant," and ordered him held in a military brig without charges.

The Bush Justice Department argued that Congress had authorized military detention of citizens at home when it authorized war against al Qaeda. But fearing a Supreme Court rebuke, the administration transferred Padilla to federal prison in early 2006, so that question has never been resolved by the Court.

But Congress can clarify the issue itself. Paul has joined 12 of his colleagues in backing the "Due Process Guarantee Act of 2011," which insists that congressional authorization for a war "shall not authorize the detention without charge or trial of a citizen…apprehended in the United States, unless an Act of Congress expressly authorizes such detention."

A decade into the War on Terror, al Qaeda is a radically diminished force. At home, it's apparently been reduced to a few hapless radicals, too dumb to realize they're being played by FBI informants.

If Congress thinks its necessary to turn America into a battlefield to address that sort of threat, the least they can do is to say so.

Gene Healy is a vice president at the Cato Institute and author of The Cult of the Presidency: America's Dangerous Devotion to Executive Power (Cato 2008). He is a columnist at the Washington Examiner, where a version of this article originally appeared. Click here to read it at that site.