Correction Appended

It’s been a rough week for Illinois Sen. Barack Obama. Instead of finally closing the deal on the Democratic presidential nomination, he was soundly defeated by New York Sen. Hillary Rodham Clinton in the Pennsylvania primary.

[IMGCAP(1)]But more than just losing another major state, his failure to attract blue-collar Democrats has raised doubts about his ability to put together a winning coalition in key big states in November.

If that weren’t enough, Obama’s former pastor, Jeremiah Wright, also re-emerged this week with defiant and impolitic appearances before the National Association for the Advancement of Colored People and the National Press Club.

Still, I suspect, his campaign is comforting itself with the notion that at least things can’t get any worse. Except they can get worse — and much worse at that.

For the first time in nearly two decades, California may now be in play for both parties, the Democrats’ worst nightmare.

Unlike Pennsylvania, Ohio and other states where Obama’s weakness with “Reagan Democrats” has kept him from wrapping up the nomination, the Hispanic vote and, to a smaller degree, the Asian vote, could well be his Achilles’ heel in California this November.

Democrats will be quick to discount this notion, rejecting out of hand any possibility that this usually reliable Democratic mega state could end up in the Republican column. But even a basic analysis of primary election and exit poll results shows that Obama may have a Hispanic problem every bit as significant as his working-class disconnect that has been so apparent in recent primaries.

Looking at the overall outcome on Super Tuesday, Clinton won the Hispanic vote by a huge 63-35 percent margin. State by state, the numbers are equally remarkable. In New Mexico, her winning margin with Hispanic voters was 26 points; 38 points in New Jersey; 35 points in California; 47 points in New York; 20 points in Massachusetts; and 14 points in Arizona.

Even in his home state of Illinois, Obama only eked out a 1-point victory over Clinton with Hispanic voters, 50-49 percent. Post Super Tuesday, Clinton won the Hispanic vote in Texas, 66-32 percent and in Maryland, 55-45 percent.

While the Hispanic vote will play a key role in a number of states, none is more important or has more potential to change the outcome of the general election than California. Democrats must win California to win the presidency, and in recent presidential elections, Republicans have all but opted out of playing in the Golden State.

It takes an enormous amount of time and money to campaign in California, and for years, the odds didn’t favor Republicans. In 2000, Gore won the state with 53-42 percent. Kerry also carried California handily with 54-44 percent.

But Obama’s weakness with Hispanic voters could be a game changer in California.

In 2000, Hispanics accounted for 14 percent of the California electorate and 21 percent in 2004. One would expect that percentage to be even higher in 2008.

A more in-depth look into the numbers shows Obama’s usual strength with younger voters doesn’t hold true for young Hispanic voters.

In California, Obama won white voters ages 18-29 by a big margin, 63-32 percent. But Clinton won younger Hispanics, who voted more like Hispanics than young people, with 65-35 percent.

Obama is also at a disadvantage in California because the African-American vote, which now gives him more than 90 percent support in most states, makes up a much smaller part of the overall electorate. In 2006, it accounted for only 5 percent of the vote, 1 point less than the Asian community, which is also not good for Obama.

Clinton won Asian voters in the California primary by a staggering 71-25 percent. Republican Gov. Arnold Schwarzenegger also won the Asian vote easily by 62-37 percent.

Ideology may also be a factor in California. When asked to self-identify in the Democratic primary, white voters broke down 58 percent liberal, 32 percent moderate and 10 percent conservative. But among Hispanics, a much lower 43 percent identified themselves as liberal, 41 percent as moderate and 11 percent as conservative. Among Asians, the breakdown was even more favorable to the GOP, coming in as 34 percent liberal, 55 percent moderate and 11 percent conservative.

Arizona Sen. John McCain may have been at odds with a part of the GOP base on immigration and other issues. But as it turns out, he may be perfectly positioned to take advantage of Obama’s Hispanic problem, not just in California, but in blue states like New Jersey as well.

In 2004, Hispanic voters made up 10 percent of the New Jersey electorate. Kerry won the state with 53 percent, close enough to make New Jersey a target state for Republicans in 2008.

Clinton’s 38-point margin over Obama with Hispanic voters in the New Jersey primary, coupled with McCain’s moderate conservatism, could be a potent prescription for a tight race in November with even small movement in key groups like Hispanics or working-class swing voters.

The media are right to focus on the fissures in Obama’s electoral strategy that fail to address his problems with the kind of working-class voters who swung to Ronald Reagan in 1980. But they need to add Hispanic and even Asian voters to the list of Obama spoilers.

For the McCain campaign, they may have to add “California Here I Come” to music on the bus.

David Winston is president of The Winston Group, a Republican polling firm.

Correction: April 29, 2008

The column originally misidentified the percentage of Hispanic votes for Sens. Barack Obama (D-Ill.) and Hillary Rodham Clinton (D-N.Y.) in the Illinois primary. Obama had a 1-point victory over Clinton among Hispanic voters, 50 percent to Clinton’s 49 percent.