Davidovich never became a citizen "because I never thought about it," she said last week from the Jewish Association Services for the Aged Shorefront Senior Center in the Brighton Beach section of Brooklyn, N.Y.

She goes there nearly every day to eat "a good kosher lunch" for 75 cents, courtesy of a subsidy from the New York City Department for the Aged.

But unless she becomes a citizen, some — if not all — of her benefits and those of countless others will cease within a year of enactment of the welfare reform bill President Clinton has pledged to sign.

The welfare overhaul has left the Jewish social service and religious establishments reeling. The new latitude it affords states and the scarcity of data on U.S. Jewish poverty make it hard for them to predict the legislation's impact. But they claim it is unjust and that it may saddle them with a crushing financial responsibility.

Diana Aviv, director of the Council of Jewish Federations in Washington, D.C., said, "The jury's out on how bad the burden will be. A lot depends on what the states decide to do."

But the cuts in SSI alone, which aids the disabled and elderly, are certain to cost the Jewish community "many millions," she said.

Beba Bereshkovsky is a social worker at the Brighton Beach senior center who came from Riga, Latvia, 20 years ago and was naturalized five years later, as soon as she qualified. She was incredulous at the news, despite what she described as the saturation coverage it is getting in the Russian press.

"You let people in at an older age and you give them benefits," she said. "You can't take this away. They came legally. They have a green card and they have a right to get benefits."

The Hebrew Immigrant Aid Society helped bring in 350,000 Jewish refugees from the former Soviet Union during the past 20 years.

Refugees — categorized as such because they have shown a well-founded fear of persecution in their homelands because of race, religion, nationality and social or political ties — will be affected by the new law five years after their arrival. At that time, they lose the special protected status that provides access to government refugee assistance in the eight months after their arrival and allows them to then apply for a range of other benefits.

Under the new law, if the refugees neither opt for citizenship nor obtain it after five years, they will be barred from SSI and food stamps and other programs from which states may choose to bar legal immigrants.

HIAS professionals estimated that thousands of Jews could lose eligibility.

The new bill will also give states the authority to deny immigrants Medicaid. There are some exceptions, including immigrants who have worked for 10 years.

Joel Karp, senior vice president of the Jewish Federation of Metropolitan Chicago, said the impact would be "devastating." If only two residents of the 240 in the local Jewish nursing home lose benefits, Karp said, "that creates a $100,000 problem" for the community.

No national data tracks the refugee population, but communities report that the elderly comprise 15 percent to 30 percent and only a small minority have sought citizenship. A 1994 survey of 12 communities, conducted for the UJA-Federation of Jewish Philanthropies of New York, shows newcomers rely heavily on public assistance.

After seven months, self-sufficiency ranged from 100 percent in Denver to 5 percent in New York City. In New York City alone, the 1990 census showed 145,000 Jews at or near the poverty level, and that was before more than 200,000 additional emigres arrived.

Even if refugees apply for citizenship at the earliest opportunity, backlogs mandate gaps of up to a year and a half, say professionals at HIAS, which brought in 21,500 Jewish refugees this year from the former Soviet Union.

HIAS in the midst of an intensive campaign to prepare immigrants for citizenship. The organization recently received more than 1,000 calls in just three hours when a new audiotape on naturalization was made available.

But some people are too frail or disabled to go through the citizenship process or too old to learn the required English skills and civics.