CARY — The Wake County school board's new Democratic majority pushed for substantive changes in the system's new assignment plan in a tense work session Tuesday, while Superintendent Tony Tata, the man behind the plan, and his Republican supporters argued for leaving it alone.

With board Chairman Kevin Hill as arbiter, Democratic board members argued that student achievement should play a greater role than proximity in assignment formulas. They specifically criticized the plan's feeder patterns, the kindergarten-to-high-school paths that students are to follow under the current plan.

"We have a responsibility as a board of nine to make sure this plan is the best for our community," said new Democratic board member Christine Kushner.

Democrats also said they want to look at setting aside a fixed percentage of seats at high-performing schools for applicants from low-performing areas.

Republican holdovers including Debra Goldman and Chris Malone said such changes were drastic and too late to put in place by next fall.

"No matter what we do, we are going to create our own winners and losers," Malone said. "I think what we need to do is as minimal change as possible right now and let staff move ahead."

But Jim Martin said they were in this position now because the board had "jumped" adoption of the new plan in October. The board, then controlled by Republicans, voted after Tata argued they couldn't afford to delay adoption.

The combative work session reflected only the latest stage in a conflict that has its roots in Wake County's decisions to balance school populations, in the 1970s by race and since 2000 by economic background. An electorate that included voters who were weary of long bus rides and frequent reassignments for some students voted in a Republican majority in 2009, and that board removed diversity from the assignment process.

In fall elections, voters changed course again, bringing in the current Democrat-led board. An immediate issue is whether to press ahead with the Republican plan adopted in October or change it before it's ever put in place.

"I feel very comfortable with the plan," Tata said after the work session. "Of course, I would listen to any good suggestions that we could implement that would make it better."

No votes were taken at the work session, but the sometimes heated exchanges showed that Democrats want to make changes, while the Republicans defended the plan that they and Tata had spent months putting together. Preliminary assignments have already gone out to 135,000 families, and fewer than 2 percent have raised problems, Tata said.

Martin, an N.C. State University professor and long-time, fiery critic of the former board, said that body's plan, built on family choice, would not achieve what its supporters promised.

"I do not see a well worked-out business plan," Martin said after the meeting.

Administrators said families from neighborhoods with many low-achieving students who don't get into their first choice will likely see their children sent to under-enrolled schools, not necessarily the high-end schools originally proposed. High-demand schools such as Lacy Elementary won't have room for the low-achieving kids, Martin said.

"There's no choice when there's no capacity," he said.

Democratic members also supported delaying the new feeder patterns for a year while the school system's staff studied them in more detail. Some parents have complained that the feeder patterns would take them out of middle schools and high schools that students in their neighborhoods now attend.

School administrators supported the plan amid the questioning by Democratic members.

"Everything in this plan isn't going to be perfect, but this is the best plan we have for going forward," said James Overman, head of the student assignment task force that developed the plan.

Goldman accused Democrats of trying to micromanage.

"Are we going to let our staff be the professionals they are trained to be and take ownership of a plan we as a board have already voted in?" Goldman said.

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