Barack Obama still won't agree to debate in Wisconsin. And now he's hiding behind false attack ads. Maybe he doesn't want to explain why his health-care plan leaves out 15 million people and Hillary's covers everyone. Or why he voted to pass billions in Bush giveaways to the oil companies, but Hillary didn't. Or why he said he might raise the retirement age and cut benefits for Social Security. But Hillary won't. Why won't Barack Obama debate these differences? Wisconsin deserves better.

- Clinton political ad

The preceding ad ended with the tag line, "I'm Hillary Clinton and I approved this message." On Tuesday, voters in Wisconsin didn't approve of the message or the messenger, favoring Barack Obama by a comfortable ratio of 58 percent to 41 percent.

Although negative ads often have worked in the past, voters are resisting them this year.

That was certainly the case in Wisconsin. Obama also won in Hawaii, creating a string of 10 consecutive victories since Super Tuesday. Obama is defeating the New York senator by expanding his support among young people, African Americans, first-time voters, independents and white males while making inroads into Clinton's core constituency.

In Wisconsin, exit polls showed Obama almost splitting the votes of white women while winning a majority of less-educated middle- and low-income voters, capturing every age group except those over 65, winning white men by roughly 25 percentage points and independents by 30 points.

Even more remarkable is the progress Obama has made since Super Tuesday, when more than 20 states held primaries or caucuses. According to an analysis by
CNN:

* Obama won 41 percent of the white vote on Super Tuesday, but 53 percent of the white vote in Wisconsin.

* He won the votes of 41 percent of white women on Super Tuesday, but 48 percent in Wisconsin.
Obama was backed by 55 percent of Wisconsin voters who considered the economy the most important issue, compared with 44 percent of similar voters on Super Tuesday.

There is a reason Obama is making such deep inroads into Clinton's base. To borrow a phrase from the women's movement, the Clinton camp just doesn't get it.

Obama is winning because he is articulating a broad vision of unity and rejecting politics of division. The more Clinton attacks, the more she's associated with the politics-as-usual gang.

Of course, neither Obama nor any other politicians should be immune from criticism. But genuine differences should be debated.

Rather than attack Clinton's Wisconsin attack ad, let's look at what neutral parties say.
Ad: "Barack Obama still won't agree to debate in Wisconsin . . . "

Fact Check.org: The two have participated in 18 previous debates, including a one-on-one in Los Angeles, and two more are planned for Texas and Ohio.

Ad: ". . . And now he's hiding behind false attack ads. Maybe he doesn't want to explain why his health-care plan leaves out 15 million people and Hillary's covers everyone . . . "

Fact Check.org: "Clinton's plan will likely cover more people than Obama's, but it's doubtful the difference between their very similar proposals would be as high as the figure Clinton cites. . . . But Obama's statement that his proposal provides 'universal' health care is also suspect."

Ad: ". . . he voted to pass billions in Bush giveaways to the oil companies, but Hillary didn't."
Jake Tapper, ABC News Fact Check Desk: "Here Clinton is taking political liberties (shocker!) with her description of the 2005 energy bill Obama supported and she opposed. The [bill] was a mixed bag, though it was certainly a disappointment to environmentalists and yes, it contained billions [in] subsidies to oil and gas companies. Is every subsidy a 'giveaway'? The bill was also supported by more than half the Democrats in the Senate at the time."
Ad: ". . . he said he might raise the retirement age and cut benefits for Social Security. But Hillary won't."

Tapper, ABC News: "That statement is misleading. Obama has never advocated those steps. . . . What he has said when asked is that 'everything needs to be on the table' (except for privatization) when it's time to address Social Security reform."

Because Clinton and Obama have such similar voting records, the central question is one of electability.
According to a recent Associated Press-Ipsos poll, Obama would be the Democrats' strongest candidate in a contest with Republican John McCain, winning 48 percent to 42 percent. Clinton was in a statistical tie, leading McCain 46 percent to 45 percent.
One reason Clinton trails Obama is the likability factor.