Falsehood, according to Mark Twain's famous dictum, gets halfway around the world before the truth even gets its shoes on. Time and again, outlandish stories seem to grow legs and find wide distribution before the truth can catch up.

A good example is the USA Patriot Act. It's so broadly demonized now, you'd never know it passed with overwhelming support in the days immediately after Sept. 11, 2001.

Critics paint the Patriot Act as a caldron of abuse and a threat to civil liberties. Advocacy groups run ads depicting anonymous hands tearing up the Constitution and a tearful old man fearful to enter a bookstore. Prominent politicians who voted for the act call for a complete overhaul, if not outright repeal.

But the truth is catching up. And the first truth is that the Patriot Act was absolutely vital to protect America's security.

Prior to 9/11, our law enforcement and intelligence agencies were limited by law in what information they could share with each other. The Patriot Act tore down that wall - and officials of both political stripes have praised the act's value.

As former Attorney General Janet Reno told the 9/11 commission, "Generally everything that's been done in the Patriot Act has been helpful, I think, while at the same time maintaining the balance with respect to civil liberties."

And as Attorney General John Ashcroft's recent report to Congress makes clear, this change in the law has real, practical consequences.

Information-sharing facilitated by the Patriot Act, for example, was critical to the successful dismantling of terror cells in Portland, Ore., Lackawanna, N.Y., and Virginia. Likewise, the information-sharing provisions contained in the act assisted the prosecution in San Diego of those involved with an al-Qaida drugs-for-weapons plot involving Stinger anti-aircraft missiles.

It also aided in the prosecution of Enaam Arnaout, an individual who had a long-standing relationship with Osama bin Laden and who used his charity organization both to obtain funds illicitly from unsuspecting Americans for terrorist organizations, such as al-Qaida, and to serve as a channel for people to contribute money knowingly to such groups.

These are not trivial successes. On the contrary, they're part of an enormous, ongoing effort to protect America from further terrorist attacks.

We cannot, of course, say that the Patriot Act alone can stop terrorism. But every time we successfully use the new tools at our disposal to thwart a terrorist organization, that's a victory.

Yet, remarkably, some of these vital provisions allowing the exchange of information between law enforcement and intelligence agencies will expire at the end of next year. So here's a second truth: If Congress does nothing, then parts of the law will return to where they were on the day before 9/11 - to a time when our government couldn't, by law, connect all the dots. Nobody wants a return to those days, but that is where we are headed if Congress does not set aside its partisan debates.

But what of the abuses, you ask? Time for a third truth: There is no abuse of the Patriot Act. None. The Justice Department's inspector general (who is required by the Patriot Act to examine the use of the act and report any abuse twice a year) has reported that there have been no instances in which the Patriot Act has been invoked to infringe on civil rights or civil liberties.

Others agree. For example, at a Judiciary Committee hearing on the Patriot Act, Democratic Sen. Dianne Feinstein of California said: "I have never had a single abuse of the Patriot Act reported to me. My staff ... asked [the ACLU] for instances of actual abuses. They ... said they had none."

So the fiction of abuse can be laid to rest. The government is not, to take but one popular myth, invading libraries and scouring your book records. It's a convenient fiction that calls to mind (as Joseph Bottum, a contributor to The Weekly Standard, has written) the appealing image of "white-haired and apple-cheeked [librarians] resisting as best they can the terrible forces of McCarthyism, evangelical Christian book-burning, middle-class hypocrisy, and Big Brother government." But no matter how appealing the image, it has no more reality than any good Hollywood movie.

Government's obligation is a dual one: to provide security against violence and to preserve civil liberty. This is not a zero-sum game. We can achieve both goals if we empower government to do sensible things while exercising oversight to prevent any real abuses of authority. The Patriot Act, with its reasonable extension of authority to allow the government to act effectively with appropriate oversight rules, meets this goal.

And the truth eventually catches up to the fiction.