WASHINGTON – The lame-duck Senate on Thursday sent President Clinton a bankruptcy overhaul bill he has promised to veto because he believes it would hurt working families that fall on hard times.

Senators, by a 70-28 veto-proof vote for the bipartisan legislation, approved the most sweeping bankruptcy law changes in 20 years, making it harder for people to erase credit card and other debts in court. Supporters have pushed for the changes over the past three years.

Voting for the bill were 53 Republicans and 17 Democrats; all the opponents were Democrats, including Connecticut’s Joseph Lieberman, the vice presidential candidate. Maine Sens. Olympia Snowe and Susan Collins both voted in support of the bill.

Sen. Peter Fitzgerald, R-Ill., voted present to avoid a potential conflict of interest because his family owns a bank. Sen. Mary Landrieu, D-La., was absent.

The House and Senate passed competing versions of the legislation, both by veto-proof margins. The current compromise measure cleared the House by voice vote on Oct. 12.

For much of the year, lawmakers have sought to reach a deal on the legislation, which has divided Democrats. Supporters in both parties have received millions of dollars in political contributions from banks and credit card companies this election year.

In the final hours of Senate debate on Thursday, one longtime opponent, Sen. Paul Wellstone, said the bill was “harsh” and he accused the banking and credit card industries of “blatant hypocrisy” for aggressively soliciting new business.

Wellstone, D-Minn., cited an academic study published in the spring that found medical bills accounted for about 40 percent of personal bankruptcy filings in 1999.

The legislation would establish a complex mathematical formula for determining whether debtors can repay part of their debts under a court-supervised plan rather than be allowed to have them dissolved.