ISLAMABAD, Aug 1 (Reuters) - When he was just a boy and his father was posted as a diplomat in Ankara during the 1950's, Pakistan's President Pervez Musharraf saw the elegant officers of Turkey's secular army and decided he wanted to be a soldier too.

Unfortunately for U.S. ally General Musharraf, with elections looming and weakened to a point where he can no longer hope to hold power alone, he needs a deal with a woman who won't let him keep his uniform -- ex-prime minister Benazir Bhutto.

After a not-so-secret rendezvous in Abu Dhabi last week, she has kept Musharraf dangling, saying "no deal" to get him re-elected president for a second term, unless he quits the army.

It may be the last card he has to play, but Musharraf, who came to power in a 1999 coup, should be reconciled to giving up his post as army chief and a uniform he calls his "second skin".

The question is when -- December or before.

"He has to cave on the uniform," said Husain Haqqani, former adviser to Pakistani leaders, including Bhutto, and now director of Boston University's Center for International Relations.

Otherwise, the only way Musharraf can keep his army job is by declaring an emergency or martial law, which he says he won't do despite growing fears of instability due to a suicide bomb campaign by Islamist militants in July.

U.S. pressure to act against al Qaeda nests in the Waziristan tribal region, and legislation tying future U.S. aid to results against the militants could further undermine Musharraf.

Western nations with troops in Afghanistan and Iraq will be unnerved by prospects of mounting instability in a nuclear-armed state, chosen as headquarters for al Qaeda's fugitive leaders.

A Musharraf-Bhutto combination seems the best option, despite doubts about how long they could work together, diplomats say.

SLUMPING RATINGS

At least Bhutto shares Musharraf's desire for Pakistan to become a progressive society, unlike some of the religious conservatives he has depended on for support up to now.

She could generate the popular backing Musharraf needs to confront the militant menace among a public more worried by rising prices, unemployment and poverty, according to a recent survey by the International Republican Institute (IRI).

For Bhutto there's the chance of a triumphant return from self-exile, exoneration from a raft of corruption charges, and a strong possibility of becoming prime minister for a third time.