WASHINGTON, D.C. — When exit polls for the Pennsylvania primary came out late Tuesday afternoon showing a puny lead of 3.6 points for Hillary Clinton against Barack Obama, Democratic leaders who desperately wanted her to end her candidacy were not cheered. They were sure that this overstated Sen. Obama's strength, as exit polls nearly always have in urban, diverse states. How was it possible, then, that Sen. Clinton, given up for dead by her party's establishment, won Pennsylvania in a 10-point landslide? The answer is the dreaded Bradley Effect.

Prominent Democrats only whisper when they compare Obama, the first African-American with a serious chance to be president, with what happened to Los Angeles' black Mayor Tom Bradley a quarter of a century ago. Exit polls in 1982 showed Bradley ahead for governor of California, but he actually lost to Republican George Deukmejian. Pollster John Zogby (who correctly predicted Clinton's double-digit win Tuesday) said what practicing Democrats would not. "I think voters face-to-face are not willing to say they would oppose an African-American candidate," Zogby told me.

If there really is a Bradley Effect in 2008, Zogby sees November peril ahead for Obama in blue states. John McCain is a potential winner not only in Pennsylvania but also Michigan, Wisconsin and Minnesota, and can retain Ohio. But there seems no way Clinton can overtake Obama's lead in delegates and the popular vote. For unelected super-delegates to deprive Obama of the nomination would so depress African-American general election votes that the nomination would be worthless. In a year when all normal political indicators point to Republican defeat on all fronts, the Democratic Party faces a deepening dilemma.

The escape route from this dilemma only a few months ago seemingly was indicated by the sudden emergence of Obama as an extraordinary candidate who could transcend race and ideology. But as Bill Clinton sought to label Obama as his wife's black opponent, he increasingly also has been identified as bearing the same ideological burdens that brought down Democratic nominees George McGovern, Walter Mondale and Michael Dukakis. It has gotten worse for Obama, losing every high-population state to Clinton except his own Illinois.

Obama hit a low in Pennsylvania, despite clouds over Clinton's credibility and her husband's dysfunctional campaigning. Popular freshman Sen. Bob Casey of Pennsylvania, a pro-life and pro-gun Catholic, was Obama's faithful surrogate but proved no help. Exit polls showed Obama losing 70 percent of Catholics, 58 percent of white Protestants and 62 percent of gun owners. Clinton carried union members, wage-earners between $15,000 and $75,000 annually, and people with less than a college degree. Obama was saved from total disaster in Pennsylvania by 92 percent of the African-American vote, but the reverse of the racial divide was Clinton's support from whites, especially white working women.

For the first time, Democratic loyalists not necessarily committed to Clinton are wondering whether the party's system for picking a nominee is the problem. If all caucuses were eliminated and only primaries used in picking nominees, Obama's lead of 130 in delegates would become an advantage for Clinton of 45 delegates. The bigger problem is proportional representation replacing the winner-take-all system that enabled Republicans to get their nominee on Feb. 5 Super Tuesday. Without the "reforms" enacted by Democrats during the decade following the party's 1968 fiasco, Clinton might have clinched the nomination by now.

Such regret does not affect the 2008 election, and no significant procedural changes are likely for the future. Democratic politicians today see no viable alternative to Barack Obama as their nominee. Their hard assessment is that Hillary Clinton clawing her way to the nomination could mean 25 percent McCain support from a radically depleted African-American turnout — a prescription for disaster.

On the other hand, Pennsylvania exit polls project a massive defection by Clinton voters (with 32 percent of them "satisfied" only if she is the nominee). Many of these disaffected Democrats surely will be reconciled to Obama. Indeed, McCain privately warns key supporters to be prepared for a massive if temporary falloff in the polls once these unhappy Democrats return after Obama is nominated. But not all will return, and that is Pennsylvania's warning to the Democratic Party.

To find out more about Robert D. Novak and read his past columns, visit the Creators Syndicate web page at www.creators.com.

COPYRIGHT 2008 CREATORS SYNDICATE, INC.