The Supreme Court's purpose in Brigham was to clear up confusions among lower courts about "the appropriate Fourth Amendment standard governing warrantless entry by law enforcement in an emergency situation." I'd call the terror war an emergency. Brigham said the Court has held that officers can make a warrantless entry "onto private property" to fight a fire, investigate its cause, prevent the imminent destruction of evidence, and engage in pursuit of a fleeing suspect. Al Qaeda qualifies as all four. Yet another precedent cited for "obviating the requirement of a warrant" is "the need to protect or preserve life." That sounds like the point of the war on terror, but some may disagree.The problem here is a conceptual "bait and switch" between the actual and the metaphorical. The court is being quite literal when they used the terms "emergency", "fire", "imminent destruction", "pursuit", and "protect or preserve life". Imminent destruction means that a terrorist is literally right in front of you with his hand on the detonator, and only immediate action can stop him. Fire means actual heat you can actually feel. Pursuit means actual running and chasing. Protecting and preserving life means pulling someone out of a burning building. Despite Henninger's overheated rhetoric, al Qaeda qualifies on none of these counts. While the plotting and scheming of shadowy transnational organizations like al Qaeda is cause for concern (and for investigative resources), it is not imminent destruction. Terrorist ideologies are alarming, but they're not the sort of "fire" you could turn an actual hose on. I hope that our government investigators are "in pursuit" of al Qaeda and their ilk, but that sort of metaphorical "pursuit" is not the kind that has anyone breathing hard and heart pounding right now. Al Qaeda per se is indeed life-threatening, but only in a very general way, with no specific threat to specific lives, more like cholesterol than like a particular ticking bomb.
It is only specific, concrete emergencies for which the Court finds it reasonable to suspend Fourth Amendment warrant requirements. Metaphorical emergencies, like the war on terror, do not apply. Most people, I think, have the common sense to tell the difference between a real emergency and a metaphorical one. Just in case, here's a test: are you running to the phone right now to call 911? If not, it's not an emergency.