Democratic Caucus Chairman Bob Menendez (N.J.), citing a Member’s scheduling conflict, postponed today’s vote on a controversial party rules change designed to keep Democrats together on key House votes.

Menendez decided to push off consideration of the rules change after Rep. Benjamin Cardin (Md.), who is bringing the proposal before the Caucus, couldn’t make the meeting. The delay also comes after two Members complained in a letter to Menendez that they needed more time to consider the idea, pushed by Minority Leader Nancy Pelosi (Calif.).

Pelosi is seeking with the change to get more leverage against Caucus defectors, according to high-level Democratic aides. The proposal would give the Steering and Policy Committee new power to approve who sits as the subcommittee chairmen or ranking members on the three “exclusive” House panels. Currently, each of the committee’s full membership decides with a final nod from the Caucus.

The change is designed to discourage members of the Appropriations, Energy and Commerce, and Ways and Means committees from voting against the Caucus out of fear they could get passed over for subcommittee leadership.

While it is expected to win overwhelming approval by the Caucus, the proposal has elicited some concern from Members who believe it would give Pelosi too much power over subcommittee assignments and hurt marginal Members who often have to buck the party.

Reps. Charlie Stenholm (Texas), a conservative Blue Dog Democrat, and Cal Dooley (Calif.), a retiring Member who has been vocal about his worries, wrote Menendez to ask the vote be postponed. They argued the delay is key because lawmakers were given only five days to look it over, and to their knowledge the proposal has “never been subject of a caucus-wide decision.”

“We believe the issue deserves a more thorough discussion between Caucus Members and see no compelling reason why the vote cannot be rescheduled to provide Members with an opportunity for further consideration,” Dooley and Stenholm wrote.

While Menendez delayed the vote because Cardin was unable to attend the Caucus meeting, he said he understands some Members’ request for a vetting period. He added that he would “be happy to oblige” those Members and postpone the vote for a week.

Leadership aides said they will use the additional time to put to rest any worries about the proposal, adding that Pelosi isn’t concerned her idea is in peril.

“Some people had some questions,” said a Democratic leadership aide. “We’re going to talk to people in the next week to address their concerns, but we don’t think there is any movement to stop it.”