BEAVERTON, Oregon (Reuters) - Democrat Barack Obama turned his focus to a U.S. general election showdown with John McCain on Friday and said the Republican White House candidate would continue the “failed policies” of President George W. Bush.

Obama gathered momentum in his battle with Hillary Clinton for the Democratic presidential nomination with endorsements from seven more senior party figures and a labor union, as well as strong praise from former Democratic rival John Edwards.

“Let’s assume Barack is the nominee, because it’s certainly headed in that direction,” Edwards told NBC’s “Today” show. He said Obama could unify the party and had a better chance than Clinton of winning November’s election against McCain.

Obama, an Illinois senator, largely ignored Clinton during his first campaign stop since taking a commanding lead in the Democratic race on Tuesday by winning a primary election in North Carolina and narrowly losing Indiana.

But he took direct aim at McCain, saying he had fundamental differences with the Arizona senator on issues like the Iraq war, taxes, gasoline prices and health care.

“John McCain wants to continue George Bush’s war in Iraq, losing thousands of lives and spending tens of billions of dollars a month to fight a war that isn’t making us safe,” Obama said in Beaverton, Oregon.

“Senator McCain is running for president to double down on George Bush’s failed policies. I am running to change them and that is what will be the fundamental difference in this election when I am the Democratic nominee for president.”

NUMBERS GAME

Obama picked up seven more “superdelegates” -- the group of nearly 800 party leaders and elected officials not bound by the state-by-state contests who are free to back any candidate at the Democratic nominating convention in August.

He was also endorsed by the American Federation of Government Employees, representing 600,000 federal workers.

Clinton, a New York senator and wife of former President Bill Clinton, won another superdelegate endorsement from Rep. Chris Carney of Pennsylvania.

“I’m gratified that we’ve got some superdelegates that are coming our way,” Obama said during a lunch stop at a taco restaurant in Woodburn, Oregon. “And I think we’ve got a strong case to make that I will be a nominee that can pull the party together and take on John McCain in the fall.”

He beamed as people in the taco shop broke into chants of “Viva Obama” and “Si se puede” -- “Yes he can” in Spanish.

Obama has now earned 13 superdelegate endorsements since Tuesday’s contests, moving closer to winning the nomination. Superdelegate support has become critical as neither candidate can clinch the nomination without them.

Among those backing Obama on Friday were Reps. Donald Payne of New Jersey, a former Clinton supporter, and Peter DeFazio of Oregon.

“At this point, Barack is the presumptive nominee,” Rep. Rahm Emanuel of Illinois, who has not endorsed anyone in the race, said at a conference in New York. “Hillary can’t win but something could happen that Barack could lose the nomination.”

With just 217 pledged delegates at stake in the final six primary contests, Clinton has no realistic chance of overtaking Obama’s lead in pledged delegates won in the state-by-state battles that began in January.

Democratic presidential candidate Senator Barack Obama steps off his plane as he arrives at Raleigh-Durham airport in North Carolina, May 5, 2008. REUTERS/Jason Reed

Obama’s campaign believes he will clinch a majority of those 217 delegates when Oregon and Kentucky vote on May 20.

CLINTON FOR VICE PRESIDENT?

Throughout the day, Obama found himself answering questions about whether he would pick Clinton as his vice presidential running mate or would consider helping pay off some of his rival’s campaign debt.

Clinton has vowed to continue running until the voting concludes on June 3, but she and campaign aides have hinted she will step aside if it is clear that Obama will be the nominee.

An MSNBC count gives Obama 1,850 delegates to Clinton’s 1,700 -- leaving him about 175 short of the 2,025 needed to clinch the Democratic nomination. More than 250 superdelegates remain undecided.

At an appearance in Portland, Oregon, Clinton criticized Obama’s health care plan for potentially leaving 15 million Americans uninsured. The United States has an estimated 47 million uninsured now.

“This is a huge difference,” Clinton said, calling health care reform “the unfinished business of our country that we have to resolve.” Clinton’s plan would require insurance for all Americans; Obama’s plan requires it only for children.

Clinton argues that she has a better chance to beat McCain in November, particularly given Obama’s difficulty in winning over white working-class voters in key battleground states.

Sixteen members of Congress and Clinton backers from states that will be critical in November’s election published a letter on Friday supporting her argument she would be the strongest candidate to lead the party in swing districts like theirs.

(Additional reporting by Donna Smith and Chris Baltimore; Writing by John Whitesides; Editing by John O’Callaghan)