Sen. Harry Reid made a failed 11th-hour stand against ending debate.
"It's not a good bill," said Reid, who also called the amendment process "unfair."
Sen. Ben Sasse (R-Neb.) wants to remove a requirement that women register for the selective service.
Lawmakers are hashing out differences between two proposals.
Sen. Mike Lee wanted a vote on his separate amendment.
Vicki Needham 06/09/16 03:33 PM EDT
Senate Democrats blasted Republicans for opposing a nominee to the Export-Import Bank board.
The move came after Republicans blocked an increase in nondefense money.
Julian Hattem 06/09/16 11:05 AM EDT
Senators pulled the bill from their calendar on Thursday, sounding a potential death knell.
Reid said he and others were "misled."
The Senate could hold a rare Friday session.