The Republican-controlled House advanced uncertainly toward a vote on historic Medicare (search) prescription drug legislation early Saturday after a day-and-night struggle punctuated by presidential lobbying calls from Air Force One.

Medicare "can't sustain itself. Add a new benefit and modernize the program," said Rep. Bill Thomas, a principal architect of the measure that would make the most sweeping changes in the program since its creation in 1965.

Democrats, pressured by their leaders to combat the bill and its supporters, did so with gusto. "We're faced tonight with people who want to destroy Medicare. They'll lie to us, they'll lie to seniors for the pure purpose of their own messianic desires," said Rep. Fortney "Pete" Stark.