ISLAMABAD, Pakistan — Pervez Musharraf, newly sworn in as a civilian president and minus his trademark general's uniform, promised Thursday to lift the state of emergency by Dec. 16 and restore Pakistan's constitution ahead of parliamentary elections.

If he keeps his word, Musharraf will have addressed key demands of opposition parties as well as the United States, an important supporter increasingly worried that Pakistani political turmoil could weaken the government's resolve to confront Islamic militants.

Musharraf urged opposition parties to participate in the election and help strengthen democracy, returning to his usually forceful persona after blinking back tears Wednesday when he resigned as commander of Pakistan's military and ended a 46-year army career.

"This is a milestone in the transition of Pakistan to the complete essence of democracy," he told officials, diplomats and generals at his oath-taking ceremony . "Anyone who is talking of any boycotts should hear this out: Come hell or high water, elections will be held on Jan. 8."

Former Prime Minister Benazir Bhutto said her party, one of two main opposition blocs, would compete in the election "under protest." She predicted the ballot would be rigged, but said it would be more dangerous to leave the election to pro-Musharraf parties.