Hillary Rodham Clinton was in her element today, brainstorming with Lockheed Martin employees about their eco-friendly diesel-electric propulsion system for buses, formulating her trademark full-paragraph responses to their questions about "incentivizing the public sector" and "importing human capital."

Lisa Coughlin was impressed by the performance, but she did wish she could ask one more question of the would-be Senate candidate in the fluorescent pink pantsuit. "I just don't understand: Why New York?" said Coughlin, 35, a financial analyst here at the Lockheed plant just outside Binghamton. "I know there's an open Senate seat. But otherwise, why New York?"

The first lady tried to answer that question today in a brief session with reporters: because New York sets the pace for the rest of the world, because it is "the Empire State" and because so many New Yorkers have been urging her to run.

It is a question that Hillary Clinton undoubtedly will be asked again and again -- is she genuinely committed to serving New Yorkers or is this opportunism tinged with chutzpah? Clinton has never lived or worked in New York and if enough New Yorkers question her rationale for her all-but-declared candidacy, she could find herself out of a job in 2000.

New York has elected out-of-staters to the Senate before, notably Robert F. Kennedy in 1964 and James Buckley in 1970, and many Binghamton-area voters interviewed today said they care much more about Clinton's ideas and record than her residency status. But others said they see the first lady's flirtation with the Senate as an insulting exercise in narcissism, a cynical power grab on the road back to the White House.

"The carpetbagger issue is the first problem she has to address," said independent pollster Maurice Carroll, whose early polls suggest that about half the state's voters are bothered by Clinton's lack of New York ties. "New York cares less about it than any other state, but the Republicans will still yell about it every step of the way."

When she emerged from the Lockheed plant today, she was greeted by protesters chanting "Go Home!" Even the local paper published a harsh editorial this week headlined "Not Senate Material."

Predictably, Clinton's potential GOP opponents are already taking potshots at her newfound interest in the state. New York Mayor Rudolph W. Giuliani has cracked jokes about running for Senate in Arkansas and is planning a July 27 fund-raiser in Little Rock. Rep. Rick Lazio (R-N.Y.) has suggested that Clinton will need her exploratory committee to locate Brooklyn, Babylon and Binghamton. The National Republican Senatorial Committee sent Clinton a tourist map of the state, along with a droll note explaining that Oxford is a small town in central New York and not just the prestigious university where her husband did not inhale.

In February, when rumors of a Clinton candidacy began to circulate, Giuliani said he didn't think being a carpetbagger was such a big deal. But now he says he's changed his mind because voters are so outraged. His campaign has a Web site devoted mostly to the subject, www.hillaryno.com, and it has received more than 3 million hits in less than three months. The mayor also gave the first lady a starring role in his most recent fund-raising letter, acidly noting that to him, "New York is not a political stepping stone."

"Look, we didn't set out to make this an issue, but it's obvious that people are offended by it," said Bruce Teitelbaum, the mayor's top political adviser and -- as he took pains to point out -- a proud graduate of the State University of New York at Binghamton. "I mean, come on. She's got no connection to the state."

The Clinton defense goes something like this: New Yorkers don't care where she's lived; they care what she can do about the issues that matter to them. And the issues that matter to New Yorkers are "family" issues that matter to all Americans: public education, child care, health care, jobs. The first lady's issues.

"Most of the problems we face here are the problems people face everywhere," said Barbara Paoletti, Democratic chairman in Broome County. "She understands those problems better than anyone else in America." Then again, Paoletti was less confident when asked why Clinton suddenly wants to address those problems in New York: "Hmm. I don't know. Maybe the diversity of the state?"

Clinton spokeswoman Marsha Berry could not shed much more light on the question. She said the first lady has been encouraged by her enthusiastic reception from New York crowds, that she believes New York is a microcosm of America, and that the Clintons had already decided to live in New York after the president's term ends. "I think New Yorkers recognize how hard she's worked on the issues that concern them," Berry said. "She's been such a dedicated public servant. I don't think people focus on where she's lived."

Still, there is agreement that Clinton will have to prove she cares about issues unique to New York: the low price of milk, the high price of air fares, the difficulty of north-south travel in the west of the state.

At today's brainstorming session, some Lockheed Martin employees were surprised when the first lady admitted she had never heard of "mag-lev," a key high-speed rail technology issue in New York over the last decade. Last week, Clinton told a Manhattan crowd that she had been to Elmira, but after local officials said they could not recall her visit, Berry clarified that the first lady only passed through once when she was a teenager.

These kinds of incidents could have a great deal of resonance in upstate New York, where the economy has lagged well behind the nation's and where residents are unusually sensitive about being snubbed. Carroll's poll found that the carpetbagger issue bothers far fewer New York City residents (29 percent) than upstate voters (53 percent) or suburbanites (62 percent), but the heavily Democratic and famously cosmopolitan city accounts for less than half the state's registered voters.

"Hillary's idea of New York is the Plaza Hotel and the Hamptons, and that's not going to play well around here," said Joe Laughney, the GOP chairman in Broome County. "Upstate, we're easily insulted."

Broome County is about three-fifths Republican, and the economy here is only beginning to recover from massive job cuts by employers such as Lockheed Martin and IBM in the late 1980s and early 1990s. But Bill Clinton won the county anyway in 1992 and 1996; New York was one of his best states in both elections. As for the first lady, she may be a carpetbagger, but she is no stranger, and many residents see her as a hero who has shown she cares about ordinary people and has suffered her husband's infidelities with grace.

"She's for children, and that's what matters," said Mildren Brush, a retired factory worker and a loyal Democrat. "I don't care where she lives; she can do a lot for New York," said Marian Anderson, a housewife and a registered Republican. "It's a marvelous idea," said retired construction worker George Sarantopolous, gesturing at a row of empty storefronts. "We need somebody to help us out, right?"

But to some of the Clinton family's critics, and even to some of their supporters, the first lady's venture into New York politics reeks of unbridled ambition. Clinton grew up in Illinois; she went to college in Massachusetts; she went to law school in Connecticut; she spent her professional life in Arkansas and Washington. The question keeps coming back: Why New York? Is it just the favorable demographics?

"I don't think people are going to be too warm and cuddly about this," said Lisa Newmark, a lawyer and a registered Democrat. "It looks like she's just using us to get an open seat."

In the end, though, even some Republicans acknowledge that the Senate race will probably come down to issues, that voters will probably vote for whichever candidate they agree with. And anyway, here in upstate New York, Clinton might not be seen as the only carpetbagger in the race. It has been more than a century since a New York City mayor won a statewide race, and if Giuliani is the GOP nominee, he will have to contend with deep-seated upstate resentments against the city he governs. Just last week, Democrats gleefully pointed out that a Giuliani press release misspelled "Niagara County."

"I'd rather vote for someone from Arkansas than someone from New York City," said Leroy Brown, 64, a former factory worker who now drives a cab in Binghamton. "That jerk Giuliani has been sending us all his welfare cases and all his criminals. He's the real carpetbagger."

CAPTION: In Johnson City, N.Y., Sharon Bryant, center, and several dozen other protesters share their opinions about a visitor, Hillary Rodham Clinton.

CAPTION: At Lockheed Martin plant in Johnson City, N.Y., Hillary Rodham Clinton takes questions with Rep. Maurice D. Hinchey. Some employees were surprised when she said she had not heard of "mag-lev" rail technology, long an issue in the state.