The Senate last night approved and sent to President Bush legislation granting almost half of U.S. workers the right to take up to 12 weeks of unpaid job leave per year to care for ill relatives and newborn children.

Although Senate passage of the measure marks an important milestone for scores of advocacy groups that have pushed the legislation for five years, the victory is likely to be bittersweet because the Bush administration has said President Bush will veto the bill. Senate passage on a voice vote and after minimal debate came one month after the House passed identical legislation.

In a statement issued yesterday by the White House's Office of Management and Budget, the administration said it "strongly opposes" the measure because it mandates that employers grant the benefit. While the administration said it supports the objective of parental and medical leave policies being provided by business, the statement said, "This objective can be best achieved voluntarily through employee-employer negotiations or the normal collective bargaining process between management and labor, not by the federal government mandating employee benefits."

The expected veto probably cannot be overcome on Capitol Hill, where the House vote on the same measure last month fell 46 votes short of the two-thirds margin needed to override a presidential veto. However, Democrats believe a Bush veto will cede them the high political ground in an election year on an issue they believe is widely supported by voters.

Democratic supporters of the legislation reminded Bush last night of his advocacy of family and medical leave during his 1988 presidential campaign. Quoting a Bush endorsement of the idea during a campaign stop in Illinois in the fall of 1988, Senate Majority Leader George J. Mitchell (D-Maine) said, "President Bush has advocated a kinder and gentler America. It's time to see whether we want to see such a nation through action or rhetoric alone."

"I urge the president to take a good close look at the bill," said the bill's sponsor, Sen. Christopher J. Dodd (D-Conn.). By signing the legislation, Dodd said, "George Bush will be living up to the commitments he made as a candidate and as a president who is deeply committed, not just rhetorically, to the American family."

The legislation guarantees employees of firms having 50 or more workers one period of leave per year of up to 12 weeks. Employees could take the leave to care for newborn, adoptive and foster children and for close relatives suffering serious illness that is certified by a physician.

Employers covered by the bill -- about 5 percent of U.S. employers -- would have to give workers either the same job or an equivalent position when they return from such leaves. In addition, employers would have to continue existing health benefits for employees on leave.

The measure is expected to cover about 44 percent of American workers, although businesses could exempt from coverage key salaried employees if they can demonstrate that providing them leave would do serious harm to the company.

Leave policies for federal employees under the legislation would be somewhat more generous, providing them with two categories of leave.

Federal workers could take up to 18 weeks of unpaid family leave over a two-year period to care for new children and up to 26 weeks of unpaid medical leave over a one-year period.

Unlike private-sector employees, who would have to deduct paid vacation and sick leave from their 12-week quota of medical and family leave, federal employees would get the family and medical leave benefits in addition to annual and sick leave.