The newest Democratic appointee to the Federal Election Commission was elected chairwoman of the agency Wednesday.

Ellen Weintraub, an election attorney, joined the commission earlier this month in a recess appointment by President Bush. She succeeds Republican David Mason as head of the commission. Republican Bradley Smith will serve as vice-chairman.

Leadership rotates on the FEC, which consists of three Democrats and three Republicans. Because the commissioner Weintraub succeeded, Democrat and Vice Chairman Karl Sandstrom, was in line to become chairman, Weintraub joined the commission in the No. 2 job and was elected to the top position Wednesday.

Smith, an attorney and former law professor, was nominated to the FEC in 2000 by then-President Bill Clinton.

Weintraub's appointment to the commission was sought by Sen. John McCain, R-Ariz., a lead sponsor of the nation's new campaign finance law. McCain contended that Sandstrom, whose term expired more than a year ago, and the commission's three GOP members were opening loopholes in the new law. Sandstrom and the Republican commissioners have said they were exercising the latitude Congress gave them to interpret the law.

Before joining the commission, Weintraub was a lawyer with the Perkins Coie law firm in Washington, where her clients included the Democratic Senatorial Campaign Committee and its House counterpart. Weintraub previously was counsel to the House ethics committee.