Fighting for his political life, a defiant Alan Hevesi last night vowed to stay in office and angrily rejected claims made by the state ethics commission this week that he abused his office by using an employee to drive around his wife at taxpayers’ expense.

Hours after Governor Pataki raised the possibility of driving Mr. Hevesi, a Democrat, out of office through a special vote in the Republican-controlled state Senate, Mr. Hevesi in a televised debate said the governor and the Senate majority leader did not have the right to decide his fate.

“It should be left up to the 5 million people who are prepared to come out to vote” on November 7, he said.

For Mr. Hevesi, his only debate against his little-known challenger, J. Christopher Callaghan, was a chance to atone and win forgiveness from Democratic Party members, such as Attorney General Eliot Spitzer, who are on the verge of deserting him.

But Mr. Hevesi’s apology, which he described more than once as “abject,” was limited. For much of the debate, he gave a full-throated defense of actions that were condemned by the ethics commission and are under criminal investigation by the Albany County district attorney’s office.

The one mistake he acknowledged was taking too long to reimburse the state for times when the chauffeuring of his wife was unrelated to protecting her security.

Mr. Hevesi, however, said he never disobeyed the ethics commission, which in 2003 permitted him to use state resources to provide transportation to his wife only when “legitimate security concerns are found to be present.”

After a unit of the state police determined that his wife, Carol Hevesi, faced a “low threat risk,” Mr. Hevesi said he took that to mean that he was entitled to take low-level security precautions to protect her and direct one of his employees, an unarmed retired janitor with no security background, to drive her.

He claimed that when he was city comptroller, Mayor Giuliani’s corporation counsel, Michael Hess, gave him permission to have a driver for his wife.

At his angriest moments, Mr. Hevesi vehemently denied that his wife was free of danger, insisting that he did not want to take any chances with her life after he received disturbing threats at his home. One such threat, he said, was a live Remington shotgun shell that was mailed to his home.

“With my wife, I’m not taking any chances,” Mr. Hevesi said. “We followed the rules but she had to have some measure of protection.”

The ethics commission said Mrs. Hevesi “did not face any appreciable security risks.”

It said: “There were no threats of any kind to Mrs. Hevesi, and any threats to Mr. Hevesi, to the extent they existed, did not warrant special protection for Mrs. Hevesi.”

Ethics officials in their report said Mr. Hevesi had no intention of reimbursing any money to the state, noting that he failed to keep time-sheet records of his wife’s driver, Nicholas Acquafredda, and did not pay back any money until a whistle-blower in the comptroller’s office leaked information about the driver to Mr. Callaghan last month.

After his complaint was reported in the press, Mr. Hevesi agreed to pay back $82,688, an amount the commission said was too low. Mr. Spitzer is investigating how much more money Mr. Hevesi owes.

Mr. Hevesi said he simply forgot to cover the cost of the driver and called his “belated” payment an aberration in his 35-year record of “integrity and honesty” as a public servant. He took credit for the increase of the state pension fund, which rose to $145 billion from $95 billion under his stewardship.

Mr. Callaghan said the increase was a factor of a rising stock market.

Smooth and articulate, Mr. Hevesi, 66, dominated the debate, which was his first major public appearance since news of the scandal broke.

The comptroller showed emotion when he described in detail his wife’s infirmity and then coolly dug into Mr. Callaghan’s record as treasurer of Saratoga County, reading from a 2002 state audit of Mr. Callaghan’s office prepared by Mr. Hevesi’s predecessor, H. Carl McCall, a Democrat. The audit described missing paperwork.

Wearing his trademark green bow tie, Mr. Callaghan seemed less like a politician and more like a guy behind the counter of a charming soda shop.

His message was simple and insistent: that Mr. Hevesi had squandered his credibility.”Your restitution was insufficient,” he said. “Your explanation was insufficient. This is a serious ethical failing and you have made yourself of no use to the people of New York in your position as fiscal watchdog.”

Republicans yesterday sought to tighten the noose around Mr. Hevesi in the hopes of pressuring him to resign before the election. A spokesman for Mr. Pataki, who is traveling in Hungary, said the governor’s office has requested thousands of pages of supporting documents from the ethics commission and is deciding who would assume the role of prosecutor in the event that the governor directs the Senate to begin removal proceedings. Mr. Pataki’s spokesman said the governor would decide by tomorrow whether to have the Senate decide on Mr. Hevesi’s fate.

The Republican Senate majority leader, Joseph Bruno, yesterday reiterated his call for Mr. Hevesi to step down and said he would await Mr. Pataki’s directions. Mr. Hevesi could be removed through an impeachment trial initiated by the Democrat-controlled Assembly, but the speaker of the house, Sheldon Silver, who is a longtime ally of Mr. Hevesi’s, has said he is resisting that option.