HERE'S one thing you're not hearing in all the coverage of the Fort Hood gunman:

Complaints that the government was reading his e-mail.

No, the outrage is just the opposite - that not only should it have been read - but also acted upon.

Most of the Monday-morning quarterbacking stems from revelations that the alleged Fort Hood shooter, Nidal Malik Hasan, sent as many as 20 e-mails to Anwar al-Awlaki. He's the imam now based in Yemen who had ties to two, maybe three of the 9/11 hijackers and whom officials have deemed an al Qaeda recruiter. (Al-Awlaki hardly tries to conceal his sympathies to radical Islam. He bragged on his Web site that the murder at Fort Hood was "a heroic act.")

All of which explains why intelligence authorities were tracking his communications. That's how the National Security Agency intercepted the e-mails exchanged between the shooter and the imam. And an ABC News report this week indicated that al-Awlaki wasn't the only connection the alleged gunman had to individuals being tracked by U.S. intelligence.

This case ends the debate.

Absent the horrific scene at Fort Hood, it's not difficult to imagine civil libertarians wringing their hands over the monitoring of e-mails whose content is, by several accounts, far from a smoking gun. Unfortunately, it took the murder of 13 and the wounding of 29 others to put the debate over electronic surveillance, the Foreign Intelligence Surveillance Act and the NSA into focus.

Fort Hood is only the most recent illustration of the potential value of domestic electronic surveillance in the war on terror.

Remember Najibullah Zazi? He's the 24-year-old born in Afghanistan, arrested in September and accused of conspiracy to use weapons of mass destruction. We now know that investigators built their case against Zazi largely on roving FISA wiretaps and the surveillance they allowed. Prosecutors allege that Zazi visited Pakistan for weapons training and meetings with al Qaeda. U.S. intelligence agents tapped into Zazi's phone and e-mail soon after.

The result? They heard Zazi discuss explosive chemical concoctions over the phone. They read text messages about bomb-making. This 21st century vigilance gave investigators the justification they needed for physical surveillance, which ultimately led to Zazi's arrest and the scattering of the sleeper cell he allegedly fronted.

In the wake of Zazi's arrest, former Attorney General Michael Mukasey wrote in the Wall Street Journal: "Those who indulge paranoid fantasies of government investigators snooping on the books they take out of the library, and who would roll back current authorities in the name of protecting civil liberties, should consider what legislation will be proposed and passed if the next Najibullah Zazi is not detected."

Unfortunately, the massacre at Fort Hood would seem to prove Mukasey's thoughts correct.

Spare me the boilerplate warnings about civil liberties, slippery slopes, and conflating all Muslims with terrorists. Nobody is saying that adherence to Islam is reason enough to tap somebody's phone. Or that the U.S. is at war with all of Islam. The country is at war with a minority segment - to which the Fort Hood killer belonged - that uses the religion to justify the slaughter of innocent people. Last week's shootings are just the latest illustration of the role electronic correspondence plays in planning those attacks.

We know convicted al Qaeda conspirator Zacarias Moussaoui was sending e-mails to flight schools in the months before Sept. 11. We also know that al Qaeda logistics coordinator Mustafa al-Hawsawi was working the phones before the attacks.

Mohamed al-Kahtani, whom the FBI has deemed the intended 20th hijacker, had Hawsawi's phone number with him when he tried to gain entry to the U.S. on Aug. 4, 2001. So did 9/11 ringleader Mohamed Atta, who dialed Hawsawi from a pay phone at Orlando International Airport on the same day.

Bottom line: The Fort Hood shootings are the latest lesson in the value of electronic surveillance in a post-9/11 world.

Eight years removed from 9/11, there's still terrorist chatter on phones and online. It shouldn't take a tragedy to put the debate about monitoring that chatter into the proper perspective.

Listen to Michael Smerconish weekdays 5-9 a.m. on the Big Talker, 1210/AM. Read him Sundays in the Inquirer. Contact him via the Web at www.smerconish.com.