Sometimes the third time's the charm. At least that's what al Qaeda hopes as it ramps up for its third assassination attempt in as many months on Pakistan's President Pervez Musharraf.

A new tape (supposedly) by al Qaeda's evil mastermind Ayman al Zawahiri last Thursday no doubt signaled Pakistani operatives to off Musharraf. The Egyptian physician-cum-terrorist called Musharraf a "traitor" and urged the Pakistani people and army to overthrow his "agent" government, which Zawahiri insists is doing the bidding of the "devil" - the United States.

Having barely eluded Musharraf's soldiers earlier in the week, Zawahiri now realizes that they, not the "Crusaders" (as he calls the United States and other infidels) are the wolves closest to the al Qaeda sled.

For his part, Musharraf now recognizes the terrorists and radicals as the greatest threat facing him.

A showdown is brewing.

The demise of Musharraf - a standup guy on terrorism of late - would be a significant blow to the global War on Terror. Pakistan is awash in radicals, terrorists and Taliban. Bomb blasts last Friday in Karachi and Jacobabad show it's still a tough neighborhood. The Pakistani house is in dire need of cleaning, and right now Musharraf is the only man to do it.

Al Qaeda terrorists have tried to get rid of him before. They hate his cooperation with the United States, his government's secular nature and his recent peace overtures toward India, especially over the issue of Indian-controlled, Muslim-majority Kashmir.

And Musharraf's aggressive, 7,500-troop anti-terror campaign in Pakistan's unruly tribal region over the last few weeks certainly has not endeared him to the terrorists, the radicals - or the locals, for that matter.

The Pakistani army's foray into South Waziristan is the first such military operation there since Pakistan became independent in 1947. Most of the tribesmen are up in arms, fearing that Pakistani security forces might infringe upon their long-held independence. (Note to tribesmen: If you want to keep your autonomy, stop protecting the terrorists.)

The foray, Pakistan's largest military counterterrorism operation to date, has thus far killed more than 50 terrorists and captured over 150 other bad guys, including Uzbeks and Chechens. The presence of al Qaeda operatives from so many different nations suggests the problem along the border is worse than once believed.

But the hunt for Taliban and terrorists along the inhospitable 1,500-mile Afghan-Pakistan border entails risks for Musharraf: It could trigger a real donnybrook with the fiercely independent tribes who live there. Military and civilian casualties already have been higher than expected.

In Greek mythology, when Hercules lopped off one of Hydra's nine heads, two grew back. The same is true in the tribal areas: Kill one local and you create, at least, two enemies. If not handled well, this could lead to more trouble than Musharraf bargained for.

Musharraf's new grit on the terrorist issue places him squarely in al Qaeda's gunsights. Resistance from terrorists, Taliban and radicals is likely to increase in the tribal areas - and beyond - to distract and divert Pakistani resources from the mission at hand.

The United States is doing its part by providing Pakistan with a five-year package of $3 billion in aid and $1.5 billion in debt forgiveness. (Last week, President Bush extended a sanctions waiver against Pakistan that had been in place since Musharraf seized power in 1999.) This is fair as there is no doubt that Musharraf's closeness with the United States comes at some political cost - and significant personal risk.

America has a lot a stake in the world's second largest Muslim nation. Failure to slay the terrorist beast could ultimately topple the Pakistani government and leave its nuclear arsenal in the hands of radicals. Instability in Pakistan would prevent the return of democracy to this secular Muslim nation and undoubtedly undermine Afghanistan's future as an open, free society.

Washington must stand by Islamabad as it deals with the terrorist scourge, providing military and economic aid, intelligence and moral support to the Musharraf government while it is under siege. Pakistan has the capability to deal with the problem, but it's Pakistani political will to do something about it that will make all the difference.

Peter Brookes is a senior fellow for National Security Affairs at the Heritage Foundation.