Since the moment it became clear that Sen. Hillary Clinton had beaten Sen. Barack Obama in both the Ohio and Texas primaries March 4, all eyes in the political world have been trained on the April 22 Pennsylvania primary.

Here we have a battleground state essential to Democratic prospects in the fall, a state suffering economically in recent years, and one in which the votes of the white working class are turning out to be increasingly crucial.

But suddenly, the Keystone State isn’t all it was cracked up to be. Hillary Clinton has widened leads in polls there, but her prospects for winning the nomination have dimmed, especially with Florida and Michigan off the table.

Now it seems that North Carolina is the new Pennsylvania.

So why is the Tarheel State ostensibly so important? Of the nine states (and Puerto Rico) still waiting to hold primaries, it’s the only one in which African-Americans make up more than 10 percent of the population.

Therefore, it’s the last real opportunity for Clinton to score a major upset against Obama. If Clinton does win North Carolina — as well as Indiana the same day, May 6, she’ll get a boost of momentum that Pennsylvania can’t offer her.

If she pulls off that trifecta, there’s a slim chance she could run the table the rest of the way, though Oregon, Montana, and South Dakota all favor Obama.

Such a feat would do little to change the math, which makes it impossible or really darn close to impossible for Hillary Clinton to finish the primary season ahead of Barack Obama in either pledged delegates or the popular vote.

But it would surely buttress the argument she is making to superdelegates: that buyer’s remorse is setting in among Democrats as they learn more about her struggling rival, and that she is the better bet against John McCain.

In Indiana, meanwhile, something unusual appears to be developing in the Democratic race: a fair fight that both sides concede is a toss-up.

Wedged between Illinois, Obama’s home state, and Ohio, where Clinton posted her critical win yet on March 4, Indiana may be the one state remaining on the calendar where both candidates begin with a roughly equal chance.

Obama’s bases of operation are likely to revolve around the Hoosier State’s three major universities - Notre Dame in the north and Indiana University and Purdue University farther south - and build out into their respective host cities.

The African-American populations that spill over from Chicago are expected to favor Barack Obama, as is Indianapolis, the state’s largest city.

Clinton, meanwhile, has the backing of the popular Sen. Evan Bayh and may have an edge over her rival on the kind of economic issues likely to dominate the discussion before the state’s Democrats vote on May 6.

While both campaigns admit the race is tight, each seeks to portray the other as the leader in the pursuit of Indiana’s 72 pledged delegates.

“We think he has some advantages starting out,” Bayh said, referring to Obama while campaigning for Clinton. “Twenty percent of Indiana households watch Chicago TV. The city of East Chicago is actually in Indiana.”

As a result, Bayh said, a big swath of Indiana is already very familiar with Barack Obama’s message and the messenger himself.

But demographics and some of the Hoosier State’s similarities to Ohio suggest that it’s Hillary Clinton, the senator from New York, has a leg up.