A measure that would effectively eliminate secret balloting for union organizing efforts has all but died in the Senate. On Tuesday, advocates mustered just 51 votes when they needed 60 to impose a limit on discussions, thereby enabling it to advance quicker.

The bill, which the House of Representatives easily passed in March, would allow a union to be certified as a bargaining agent when more than half of the employees at a work site signed cards. Many employers, including long-term care providers, oppose the bill, claiming it could allow union organizers to easily intimidate workers.

The Senate’s vote generally followed party lines. President Bush has threatened to veto the measure if it reaches his desk.