The Senate today may take its first votes on amendments to the financial-overhaul bill, beginning with a proposal to ban taxpayer-funded bailouts of Wall Street firms. The Senate resumes debate on an amendment offered by Senator Barbara Boxer, a California Democrat, that would ban spending taxpayer funds to keep failing firms in business and require firms seized by regulators to be liquidated. Votes will start “maybe as soon as” today, Illinois Senator Dick Durbin, the No. 2 Senate Democrat, said yesterday. “There’s nothing more important we do in this bill than to end the too-big-to-fail concept,” Senate Banking Committee chairman Christopher Dodd, a Connecticut Democrat who offered the bill, said yesterday.