Sen. Ron Wyden (D-Ore.) used a rare parliamentary maneuver yesterday to block a Senate Commerce Committee vote on President Bush's nomination to head the Federal Trade Commission -- angering Chairman John McCain (R-Ariz.) in the process.

Wyden has opposed the nomination of antitrust lawyer Deborah P. Majoras over concerns that she would not actively police the oil industry from using anticompetitive practices to drive up gasoline prices.

McCain sought to have her nomination considered at the start of the 9:30 a.m. meeting, but Wyden pressed for a delay until the committee had completed other work. McCain agreed. But around 11:30, while the committee adjourned for a Senate vote, Wyden invoked a rule limiting hearings to two hours when the Senate is in session. Also delayed by the dispute is the nomination of Jon D. Leibowitz to be a Democratic FTC member.

"I have never been deceived like that in the 22 years I've been here," McCain said in a later phone interview. McCain said that he had agreed to put off the vote as a "courtesy" to Wyden. "It will be impossible for me to do business with Senator Wyden" in the future, he said.

In a statement, Wyden said, he took "this extraordinary step to send a clear message that protecting consumers is of the utmost importance, especially in the face of record high gas and energy prices." He was particularly critical of Majoras's refusal to take a stand on a recent government study linking higher gasoline prices to oil industry mergers approved by the FTC. Majoras said she would study the issue. Wyden said that was insufficient.

Several other Democrats have expressed concerns about Majoras's nomination, as have some consumer groups. Committee aides had predicted a vote along mostly party lines, which would have meant approval. Wyden's action led some to wonder if Bush might now appoint Majoras as chairman while the Senate is in summer recess. She could then serve as chairman until 2005, when the present Congress adjourns.

Erin Healy, a White House spokeswoman, declined to comment on that prospect. But she said, "It's unfortunate that a minority of senators continue to obstruct the confirmation process and the president urges the Senate to stop playing politics with his nominee and give her the up-or-down vote she deserves."