It's a war. Whenever we begin to forget that, we get a horrific reminder.

This summer the air palpably began to leave the war on terror. In the U.S., media coverage gravitated to shark attacks and missing girls — just as it had prior to Sept. 11. The world, at least that portion of it represented by the G-8 summit, had focused its attention on self-flagellating debates about who is and who is not providing enough humanitarian aid to Africa.

We had "moved on," or at least were trying to. But just as President Bush had hoped to move on from Iraq to domestic issues after the successful Jan. 30 elections, only to learn that a live shooting war cannot be ignored, so it is that the larger struggle with al Qaeda and its affiliates cannot be ignored either, because it too is a live shooting war. British Prime Minister Tony Blair's efforts to placate Bono and friends on global poverty look faintly ridiculous now that the London attacks have laid bare what should be his chief duty and that of other Western leaders — protecting the public from slaughter.

We are facing a global insurgency of Islamic militants who will hit anywhere, from Mosul to London. Their goal is totalist. They want, first, to drive us from the Middle East, then, to establish a caliphate there, and finally, to absorb the West into their theocracy. If this seems absurd, well, fanatical murderers are not usually known for their finely modulated objectives.

Critics of Bush and Blair argue that the Iraq war has nothing to do with the war on terror. But the terrorists have always known better. They realize that Arab radicalism's loss of Iraq and the establishment in Baghdad of a decent, stable, antiterrorist state would be a grave ideological blow. So it is probably no accident that two of the most high-profile terror attacks since 9/11 have been directed at Spain and Britain, whose leaders stood with Bush in a key meeting at the Azores islands in Portugal in March 2003 to give Saddam Hussein one of his last ultimatums.

The Spanish cut and ran from Iraq after the Madrid train bombings in 2004, hoping to take the target off their back, but painting one all the larger on the backs of any countries supporting the fight against extremism in Iraq. The Brits, having suffered much worse during the Blitz and the height of the IRA bombing campaign in the 1970s, won't surrender so easily.

In this war someone can be on the front lines whether he is on a bus in Tavistock Square or on a U.S. Army helicopter in Jalalabad. Unfortunately, there are limits to how much can be done to protect the home front, which is why it is preferable to try to kill terrorists and sap them of their ideological energy overseas. Commercial aviation appears pretty well locked down in the West — or so one hopes — but mass transit, with its multitude of access points and its countless fast-moving passengers, is impossible to secure in a similar fashion.

Americans can take some cold comfort in the fact that al Qaeda surely would prefer to hit here in the States, but seemingly can't manage it. Such an attack, of course, could take place tomorrow. But that it hasn't yet is probably some testament to the efficacy of the Patriot Act, the immediate detention of hundreds of Muslim immigration violators after 9/11 (most, no doubt, innocent of any evil intention, but perhaps a crucial handful not), and tighter border control in general. Britain passed a new Prevention of Terrorism Bill only in March and, like most European countries, has relatively lax immigration and asylum policies.

Of course, all of these antiterror initiatives in the U.S. have been criticized by the ACLU and the usual suspects on the left. What they don't acknowledge is what we've been reminded of yet again — it's a war.