MOBILE, ALA., JULY 30 -- Democratic Congressional leaders reacted with anger today to the decision by the nation's governors to keep Congress out of their new approach to scorekeeping on the performance of school systems in every state.

Senate Majority Leader George J. Mitchell (D-Maine) called the Sunday action "a mistake" by the executive committee of the National Governors Association, meeting here. Without full participation by Congress in the assessment process, he said, "there isn't going to be any change" in the quality of U.S. education.

Rep. Pat Williams (D-Mont.), sponsor of House-passed legislation that would have the assessment panel appointed by Congress and include education experts, but no governors, said the governors' effort will "run head-on into an adamant Congress" and be overruled.

The governors' plan would limit the panel to six governors and four administration officials, with Congress offered only four nonvoting members. In a phone call to the governors' meeting, President Bush said that plan "makes good sense."

Bush said he was well satisfied with the design of the assessment group, which would be charged with issuing annual reports on state and federal action to meet the six national education goals that Bush and the governors hammered out at the education summit in Charlottesville, Va., last September and in follow-up meetings last February.

Williams, a principal sponsor of the bill creating the congressionally appointed assessment board, reacted caustically. "I've gone through the resumes of the president and the 50 governors," he said, "and if you could find 51 elected officials who know less about education, I doubt it."

He argued that the reform effort can succeed only if the assessment involves "a broad cross section of the American people," including representatives of teachers' unions and other education groups.

But after a meeting with White House officials Sunday, the governors' executive committee voted unanimously not to heed a letter from Mitchell and House Speaker Thomas S. Foley (D-Wash.) asking them to postpone creation of the assessment board until Congress completes action on the House-passed bill. Bush has threatened to veto the bill in its present form, and White House Chief of Staff John H. Sununu has criticized Williams's plan to include what Sununu called "education trade groups" in the assessment process.

Arkansas Gov. Bill Clinton (D), one of the lead governors on education, predicted that the National Governors Association executive committee action will be approved by the full membership.

"Pat {Williams} has been in Congress while the share of the budget going to education has been cut 30 percent, and in all this time, Congress has made no contribution to education reform," Clinton said.

"Some of us wanted to have the four members of Congress {on the assessment board} have a vote," Clinton continued, "but it was the former members of Congress who are now governors who said that would be a terrible mistake. His {Williams's} comments indicate they may have been right."

The governors also moved into the politically explosive health policy field, which incoming association chairman, Washington Gov. Booth Gardner (D), has selected as the focus for the coming year.

Two consultants warned them that surveys show working- and middle-class Americans feel their medical insurance needs are as urgent as those of the poor and will look skeptically at any proposal that would raise their taxes to benefit poor people.