ALBANY – Quickly, now: Who is the lieutenant governor of New York?

The answer, Mary Donohue, may not come immediately to most New Yorkers’ lips, but her identity takes on added significance as Governor Pataki travels in Europe for the next 10 days.

According to the state constitution – Article IV, Section 5 – the lieutenant governor “shall act as governor” whenever the governor “is impeached, is absent from the state, or is otherwise unable to discharge the powers and duties of the office of governor.”

The clause, which dates to an era before telephones, jet travel, and e-mail, is subject to conflicting interpretations. Ms. Donohue has not exercised her theoretical authority during past gubernatorial trips, nor is there any indication she intends to do so now. Yet in the minds of some experts she is the acting governor regardless of whether she accepts the title.

“I’m not aware of any reason why the constitution doesn’t mean what it says,” a lawyer who was counsel to governors Rockefeller and Wilson, Michael Whiteman, told The New York Sun. “If something has to be signed, as a technical matter, I would take the position that the lieutenant governor has to sign it.”

Neither Ms. Donohue nor her press aide, Matt Andrus, returned phone messages from the Sun yesterday.

A spokesman for the governor, Todd Alhart, repeated what has been the administration’s position on the issue during Mr. Pataki’s many out-of-state trips. “Whether the governor is in Washington or any other place, he is still the Governor,” he said in an e-mailed statement. “And given the modern-day technology that exists in the 21st century, he’s in contact with his senior staff on a regular basis.”

Mr. Pataki left Sunday to visit unspecified countries in Central Europe on what he described as a family vacation. He is due back December 30.

An expert on the state constitution at Albany Law School, Vincent Bonventre, said he supported the administration’s view. He said it’s clear from the context that the framers – whose fastest means of travel was horses – assumed that a governor who was outside the state would be “unable to discharge” his powers and duties.

Nowadays, “if anything really did arise which required the governor, he could just fly right back,” Mr. Bonventre said. “It seems to me he’s fully capable of discharging his duties. …

“If he couldn’t make it back and something had to be acted upon, then I think there’d be a much better case that the lieutenant governor could act in his stead,” he said. “But just being outside the border of the state is hardly what the constitution is talking about.”

According to Mr. Whiteman, however, Rockefeller’s lieutenant governor, Malcolm Wilson, would occasionally sign documents as acting governor when Rockefeller was out of state. Wilson became governor in 1973, when Rockefeller left Albany to become vice president.

“There was a great deal of rapport and trust and respect between Rockefeller and Wilson, and I don’t believe Governor Wilson would have ever contemplated doing anything in his role as acting governor that would not have met with the approval of Governor Rockefeller,” Mr. Whiteman said. “As a consequence Rockefeller felt able to travel freely and did – out of the state, out of the country – in utter confidence that things would go on in New York exactly as if he had been here himself.”

Mr. Whiteman recalled that in 1968, during the Republican National Convention, Rockefeller, Wilson, the Senate majority leader, and the speaker of the Assembly were all absent from the state at the same time – leaving the then-majority leader of the Assembly, Moses Weinstein of Queens, as acting governor.

“He called me up and said, ‘I know you won’t let me do anything dramatic. … But I would like to do at least one thing as acting governor,'” Mr. Whiteman said. “I said, ‘Well, as a matter of a fact, I have two or three extradition warrants that need to be signed. He said, ‘I’ll do it for you!'”

“There’s no reason why it shouldn’t be done that way,” he said. “It’s technically correct.”

The counsel to Governor Cuomo, Evan Davis, said he could not recall Lieutenant Governor Stanley Lundine ever serving as acting governor. He added, however, that Mr. Cuomo rarely spent even a single night away from the governor’s mansion during his three terms.

“We would not have had him sign [official documents] out of the state,” Mr. Davis said. “But because he was always so eager, for whatever reasons, to be home, it just did not come up.”

An assemblyman calling for an overhaul of the state constitution, Richard Brodsky of Westchester County, said he thinks the “absent from the state” clause should be deleted.

“It’s a clearly outmoded provision, and in this fundamental reform package we put together, we fix it,” Mr. Brodsky said.

Since winning her office in 1998, Ms. Donohue – a former teacher, district attorney, and state Supreme Court judge – has kept a low profile as the woman who is a heartbeat away from the governor’s office. Mr. Pataki has put her in charge of task forces on violence in schools, on “smart growth” initiatives to manage urban sprawl, and on small business. She occasionally presides over sessions of the Senate, rarely seeks press attention, and never stakes out positions in conflict with the governor’s.

Her relative invisibility contrasts sharply with Mr. Pataki’s first running mate, Betsy McCaughey, a think-tank scholar who served as lieutenant governor from 1995 through 1998.Opinionated and outspoken, Ms. McCaughey played a prominent role as head of a Medicaid task force in the early days of the Pataki administration. Later, she feuded bitterly with the governor and his aides and briefly ran against him in the 1998 campaign.