Donald A. Ritchie, the associate Senate historian, says the modern use of the hold began in the 1950s under the leadership of Senator Lyndon B. Johnson, who increased the use of unanimous consent agreements to bring more order to the Senate. Holds were initially allowed as a courtesy to senators who needed more time to get to the chamber to object in person, read the bill or try to negotiate changes with the sponsor.

But their use has proliferated and intensified to the point where lawmakers employ them not only to lodge substantive objections to legislation, but also to stall nominations and bills routinely in retaliation for other actions or to win concessions. Though leaders can break a hold with a 60-vote majority, they have often been reluctant to do so out of respect for the tradition — and the chance they might want to impose a hold of their own some day.

Some senators — remember Jesse Helms? — revel in their holds and wield them publicly like a blunt instrument. In 2003, Senator Larry E. Craig, Republican of Idaho, openly put holds on 850 Air Force promotions while he demanded cargo planes for the Air National Guard in his state.

Others are more surreptitious. Watchdog groups and some Democratic senators are still trying to identify the Republicans who put a hold this year on a proposal to require senators to file campaign contribution reports electronically.

In reality, even anonymous holds are not completely confidential because cloakroom staff members and party leaders typically either know who placed the holds or they eventually find out. But the names of those who use holds often remain hidden from the public and from many colleagues. Several senators said Wednesday that the new disclosure requirements would improve the culture of the Senate.

“I think it has been a bad practice forever,” said Senator Arlen Specter, Republican of Pennsylvania. “I think it will improve things around here if people have to stand up when they oppose legislation. Give a reason and let it come up for a vote.”

Under the proposed rule, any senator who instituted a hold would be required within six days after raising it to submit a Notice of Intent to Object to Proceeding that would state their name, the date, the matter at hand and the reason for issuing the hold. Any hold lifted within six Senate working days after it is placed would not have to be disclosed.