ALBANY, N.Y. — Governor Pataki, breaking ranks with President Bush and the front-runners for the 2008 Republican presidential nomination, says he opposes the president’s plan to send more than 20,000 additional American troops to Iraq.

Mr. Pataki’s position, at odds with the support offered to Mr. Bush by Senator McCain, Mayor Giuliani, and Governor Romney of Massachusetts, was made public yesterday as aides released excerpts of a speech the former governor is to deliver Friday at Georgetown University.

“A functioning democracy throughout Iraq is not essential to our achieving a military victory over Al Qaeda in Iraq,” Mr. Pataki, who is eyeing a run for the 2008 nomination, said. “And I share the doubt of many that 20,000 additional troops alone will assure a successful democracy.”

“Sending more American troops into Baghdad is unnecessary to achieve the core victory over Al Qaeda in Iraq,” he added. “A troop ‘surge’ is better suited as part of the effort to achieve a broader victory. But I oppose carrying out this surge unless the prospects for that broader victory are much greater than they appear today.”

Mr. Pataki, whose eldest son is a Marine facing possible deployment to Iraq, said, “Before the United States government puts more troops in harm’s way in Baghdad we must have confidence that the Maliki government will be an active partner in this effort.”

Pataki spokesman David Catalfamo said the former governor wasn’t ruling out possible future support for the Bush-backed initiative, but only if the Iraqi government proved it was getting control of the country and taking on more of the responsibility for security there.

“We must detail to the Iraqi government the terms under which we will continue to prop up its weak and struggling institutions,” Mr. Pataki said. “If they want Americans to continue to die in defense of their government, if they want Americans to continue to pour tens of billions of dollars into their people’s schools, services, and security, we can and must first demand action on their part.”

While Mr. Pataki’s comments appeared as a sharp departure from his past support of Mr. Bush on the Iraq war, the former governor began expressing reservations about the American policy on Iraq after a November trip to the war zone when he said the Iraq government “is not delivering the security or the services that the people of Iraq need. That has to change and that has to change quickly.”

The remarks released yesterday make it clear that Mr. Pataki believes that had not happened.

“An oppressive majority can ignore the rule of law or use the power of government to deny opposition groups basic human rights,” he said. “Unconstrained majorities can act in the interest of good or evil, or simply choose not to react to the evil of others. To a large extent, that has happened in Iraq.”

Catalfamo said he did not expect Pataki, who chose not to seek reelection last year after three, four-year terms as governor in heavily Democratic New York, to use the speech to announce his intentions about running for president.