By TERENCE HUNT

The Associated Press

WASHINGTON — Weary of war and angry at the president who started it, Americans vented their frustration at Washington’s power structure Tuesday. It was a clear call for change aimed at President Bush and a Republican Congress that has marched in step behind the commander in chief.

Republicans worried that the sour mood of voters in midterm elections would cost them control of the House after 12 years and possibly the Senate. Bush insisted to the end that Republicans would defy the odds and remain in charge. But early returns and exit polls of voters gave Republicans little to cheer about.

Needing a gain of 15 seats to win the House, Democrats won 13 Republican-held districts and battled for more. Republicans lost the Ohio seat held by Bob Ney, who resigned after pleading guilty in a lobbying scandal.

In fact, three-fourths of voters said corruption and scandal were important to their votes, and those voters were more likely to vote for Democratic candidates for the House.

In the Senate, Democrats beat incumbent Republicans in Ohio, Rhode Island and Pennsylvania. Democrats needed a pickup of six seats to win the Senate.

Democrats also won gubernatorial races in New York, Ohio and Massachusetts for the first time in more than a decade.

“It’s very hard to watch,” former House Republican Leader Dick Armey said of the returns.

Six years into Bush’s administration, the election stood as a referendum on his presidency, which has been weakened by high gasoline prices, economic insecurity and the government’s sluggish response to Hurricane Katrina. Far more voters said national issues mattered more than local issues in their House vote, and a majority worried that the nation is seriously off on the wrong track.

A turnover in the House or Senate would give Democrats a big voice in setting the nation’s agenda and the power to challenge Bush’s conduct of the war. Democrats campaigned on a platform of change, from the top down. Rep. Nancy Pelosi of California would become the nation’s first female House speaker if Democrats gained a majority.

“I think regardless of the results, today is really a referendum on President Bush’s handing of the war in Iraq and whether we should bring the troops home,” Sen. Edward M. Kennedy said.