(Agencies)
Updated: 2008-04-23 16:49

PITTSBURGH -- Why can't Barack Obama put Hillary Clinton away?

He's flush with cash. He oversees a high-tech political movement. His "change" message fits these anxious times. And, until recently, he had momentum. So why didn't he win Tuesday?

And why can't he close the deal?

Democratic presidential candidate Senator Barack Obama (D-IL) gets a hug from a supporter at his Pennsylvania primary election night rally in Evansville, Indiana, April 22, 2008. Indiana will hold one of the next Democratic primary elections on May 6. [Agencies]

In the short term, it may not matter because Clinton's victory in Pennsylvania is unlikely to change the dynamic of the nomination fight: It's Obama's to lose; it has been since late February when Wisconsin Democrats handed him a 10th consecutive victory and an almost insurmountable lead in pledged delegates.

Longer term, he's got problems. Here are five reasons why Clinton is still alive. Five ways he'd be vulnerable in November.

RACE: The jury is still out on whether a black man can overcome America's original sin and be elected president.

About one in five Pennsylvania voters said the race of the candidates was among the top factors in deciding how to vote, according to exit polls, and white voters who cited race supported Clinton over Obama by a 3-to-1 margin.

Results from all the primaries suggest that whites who said race was important in picking their candidate have been about twice as likely to back Clinton as Obama.

An AP-Yahoo News poll found that about 8 percent of whites would be uncomfortable voting for a black president. The actual percentage is probably higher because voters are shy about admitting a racial prejudice to pollsters.

Both campaigns exploited the race issue. The Clinton camp maneuvered to cast Obama as a candidate whose appeal was limited to blacks. The Obama campaign seized every opportunity -- at times overreaching -- to accuse the Clinton campaign of playing the race card.

The issue was renewed when former President Clinton, asked in an interview broadcast Tuesday with Philadelphia radio station WHYY about comments he made before the South Carolina primary, said the Obama campaign "played the race card on me."

"And we now know, from memos from the campaign and everything, that they planned to do it all along," Bill Clinton said.

WORKING-CLASS VOTERS: Obama can't win the presidency unless he starts connecting better with blue-collar voters.

The New York senator easily won among Pennsylvania voters without college degrees and those from families earning less than $50,000 a year. Gun owners, rural voters and churchgoing Democrats also backed Clinton.

These are the folks who Obama said "cling to" guns and God, an inelegant attempt to explain to San Francisco liberals how GOP operatives exploit Democratic voters in anxious economic times. He bowled (poorly) and drank beer in a feeble attempt to show a blue-collar touch.

If Obama wins the nomination, he risks losing those voters to Republican John McCain. While 68 percent of Obama voters in Pennsylvania said they would vote for Clinton should she run against McCain, just 53 percent of Clinton voters said they would vote for Obama.

Race may be an issue here, too. For years, Republicans aimed affirmative action, school busing, welfare and other racially tinged wedge issues at white working-class voters.

FRIENDS IN TROUBLE: The longer the campaign goes, the more questions Obama faces about his friends and associates.

He was forced onto the defensive by incendiary comments by his pastor, the Rev. Jeremiah Wright. Friend and fundraiser Antoin "Tony" Rezko faces corruption charges. And McCain is raising questions about Obama's relationship with former 1960s radical William Ayers, who has been quoted in an interview as saying, "I don't regret setting bombs" decades ago.

INEXPERIENCE: It's true that Clinton has never run a government or a business, but many voters give her credit for proximity. They consider her experience as first lady preparation for the presidency.

By any measure, Obama is relatively inexperienced, having left the Illinois Legislature less than four years ago.

METTLE: Clinton's backers love the fact that she fought Republicans -- not to mention the "right-wing conspiracy" -- during her husband's presidency. Many Democrats wonder whether Obama is tough enough, a charge that he should be putting to rest in this brass-knuckle nominating contest. But he hasn't.

Headed into Pennsylvania, the cash-strapped Clinton had to defeat Obama by a wide enough margin to stay in the race, raise money and eventually persuade a majority of party regulars -- the so-called superdelegates -- to side against Obama.

Victory in hand, she must keep winning -- Indiana, North Carolina, Oregon, Kentucky, West Virginia, Puerto Rico and beyond, all tall orders, and catch every break along the way.

"He broke every spending record in this state, trying to knock us out of the race," Clinton crowed in victory Tuesday night. "Well, the people of Pennsylvania had other ideas."

The question is whether superdelegates will get other ideas. Will they start wondering why can't Obama put her away?