Islamabad, Pakistan ? Pakistan’s next army chief owes his meteoric rise to Gen. Pervez Musharraf, but was once a confidant and senior aide to the Pakistani leader’s archrival Benazir Bhutto. He is well-known in Washington but has a reputation for keeping his cards close to his chest.

However Pakistan’s political crisis unfolds, Gen. Ashfaq Kayani will play a key role in either propping Musharraf up or accelerating his political demise.

Musharraf has named the 55-year-old career officer to take control of Pakistan’s 600,000-strong armed forces when he gives up his title as army chief, something Musharraf has said he expects to do by the end of this month.

But pressure is mounting on Musharraf to go further, by resigning as president and exiting the stage altogether. Musharraf declared emergency rule two weeks ago, disbanding the Supreme Court and jailing thousands of his detractors, including senior political leaders.

He has vowed to stay on as a civilian president, though his base of support appears to be thinning, both here and in Western capitals. Analysts say the support of Kayani and the other generals is vital to his political survival.

If Musharraf leaves the scene abruptly, Kayani could find himself in control of this nuclear-armed nation on the front lines of the U.S. war on terrorism. And even if Musharraf stays on as a civilian president, he will be reliant on Kayani’s military for support.

Kayani studied at the prestigious U.S. Army Command and General Staff College at Fort Leavenworth, Kan.