Senator Sam Nunn, a Georgia Democrat who was one of the last remaining undecided senators, announced his opposition today.

Earlier in the day, Republicans had cobbled together a proposal governing how witnesses would be handled, hoping it would assuage undecided senators in both parties.

Doubts about Judge Bork's views on some of those issues turned undecided senators against him.

Proponents of the science hoped his endorsement would help sway undecided senators, especially conservative Republicans.

He urged them to try to win over pivotal undecided senators or risk losing a proposed tax credit for wind, solar and geothermal power.

Mrs. Reagan spent this week calling undecided senators to urge them to vote for the bill.

Senator Heflin and other undecided senators placed special stress on concern about whether Judge Bork would seek to overrule the many precedents he has assailed.

He said there remained "a lot of undecided senators," adding, "The stakes are enormously high."