Barack Obama ran his winning streak to nine states yesterday with a double-digit victory over Hillary Clinton in Wisconsin that set the stage for potentially crucial primaries a week from Tuesday.

Obama, 46, whose chances of becoming the Democratic nominee continue to brighten, was expected to add a 10th-consecutive state early today when caucus results were tallied in his native Hawaii.

The Republican race, meanwhile, was nearing an end after John McCain won easily in Wisconsin.

"I will be our party's nominee," declared the Arizona senator, 71, now positioned to clinch the nomination as early as March 4. McCain used his victory speech last night to criticize what he termed Obama's lack of experience in foreign policy.

Obama, addressing a huge rally in Houston, said: "The change we seek is still months and miles away. ... We will need you to fight for every delegate it takes to win this nomination."

Clinton, who last won Feb. 5, is falling further behind in the delegate count. Party rules make it increasingly tough for her to regain the lead without a drastic shift in the direction of the race.

Addressing supporters in Youngstown, Ohio, she returned to her attack themes of the past week and asserted that Obama is unprepared to serve as commander in chief in a dangerous world.

"Only one of us is ready on Day One," said Clinton, who has made her experience the message of her candidacy. Increasingly, some of her supporters have criticized that strategy as Obama has started pulling away in a nomination race that appears to be turning on voters' desire for change.

Since Super Tuesday, everything has gone Obama's way, and there have been few, if any, signs that Clinton can stop him.

As he did in last week's Potomac Primaries, Obama ate into Clinton's coalition of women, working-class whites and older voters. White voters cast almost nine of 10 primary votes in Wisconsin, and Obama won a majority of them.

He split the votes of white women, Clinton's strongest support group, and won every age group except those over 65. He carried white men by roughly 25 percentage points, a key indicator heading into the Ohio primary.

Clinton has yet to demonstrate the breadth of support she would need to convince her party's superdelegates that she's the Democrat who can win in November.

Instead, in Wisconsin, Obama won big among independent swing voters, who might hold the key to the fall election. Independents and Republicans cast more than one-third of the Democratic vote, and Obama carried them by a 2-to-1 margin, according to an Election Day survey of voters as they left polling places.

His crossover appeal could be a pivotal factor in the next primaries, in Ohio and Texas, which allow independents to participate. Ohio, with its large, white, working-class electorate, has emerged as a must-win for Clinton.

As he did last week in Maryland, Obama won an increasing share of white working-class voters, running even with Clinton among those who earn $15,000 to $30,000 a year and those without a college education. He also ran almost even with her among Catholics, who cast about two in five votes.

An overwhelming majority of Wisconsin's Democratic voters took a sharply negative view of the North American Free Trade Agreement from the Bill Clinton years. About seven in 10 said it had cost the country jobs, and Obama won most of their votes.

Obama has sought to tie NAFTA to Hillary Clinton, who initially supported it but more recently has criticized the way it was enforced, and called for a "timeout" on future trade deals.

Clinton's campaign has argued that her victories have come in states that a Democrat would need to carry in November, while many of Obama's have come in heavily Republican states.

However, Wisconsin figures to be a major battleground in the general election. It has been almost dead even in the past two presidential elections, going Democratic by an eyelash both times.

The tone of the Democratic race turned sharply negative last week, after Clinton launched attacks on Obama over issues such as Social Security and his refusal to debate her in Wisconsin.

Clinton aides have accused Obama of plagiarism, for using identical phrases in speeches that Deval Patrick, the first black governor of Massachusetts, used in his.

Obama has fought back, with response ads in Wisconsin and attacks of his own at campaign events. Yesterday, during his first stop in Texas, he criticized Clinton's plan for a five-year interest-rate freeze on adjustable-rate mortgages, warning that it could deepen the subprime lending crisis.

"Even more families could face foreclosure," he said in San Antonio. "That's why one economic analyst called her plan disastrous."

Obama and Clinton will debate twice over the next six days. They'll face off tomorrow night in Austin, the Texas capital, and next Tuesday in Cleveland, Ohio.

Those encounters could offer Clinton her last, best chance to knock Obama off stride as their battle heads into what could be a decisive day of primaries March 4 in Texas, Ohio, Rhode Island and Vermont.

Wisconsin's primary electorate - overwhelmingly white, with a large segment of rural and working-class voters - seemed well-suited to Clinton's candidacy.

Her campaign initially seemed uncertain about whether to compete aggressively, delaying her personal appearances there until late last week. But she boosted her advertising buy in the final days of the race.

Obama made more campaign stops and outspent Clinton in the state.

His recent successes appear to be momentum-driven, a growing problem for Clinton.

Landslide victories last week in the Potomac Primaries appeared to have influenced voters in other states. In Texas, a state where Clinton had led by double-digit margins, a CNN poll released this week showed the contest a statistical dead heat.

More than 30 states have voted since the Iowa caucuses Jan. 3, seven weeks ago.

Now, for the first time since the unprecedented crush of early primaries and caucuses, it will be two weeks until the next set of contests.

Clinton's top strategist, Mark Penn, said in a conference call that Ohio is "a state we can win."

He stopped short of calling Ohio a must win for Clinton, though many Democrats have said that if she loses there, her candidacy could be in dire trouble.

Clinton victories in Ohio and Texas "would be very powerful in terms of superdelegates," said Penn, referring to the 796 elected officials and party activists who could hold the balance of power in the nomination fight.

paul.west@baltsun.com