Not since 1980, when beleaguered President Carter was being challenged by U.S. Sen. Ted Kennedy for the Democratic nomination, has Pennsylvania mattered in the presidential primary.

Now, it’s become the Keystone Battleground, ironically due in part because of state lawmakers’ inability to move up the primary to raise its significance.

But the intense Democratic race between U.S. Sens. Barack Obama and Hillary Clinton may be more about perception than delegates, experts said.

A composite of polls shows Clinton has about a 10-point lead over Obama leading up to the April 22 primary, said G. Terry Madonna, a political analyst from Franklin and Marshall University in Lancaster.

If she wins as expected, she can carry the momentum into other remaining primaries, the Democratic convention and the struggle for superdelegates.

“If she loses the state,” Madonna said, “she’s done.”

Obama’s strategy essentially will be to keep the race close, Madonna said.

“It’s not going to move the delegates very much,” he said. “It can maybe get her seven or eight more.

“But if she loses Pennsylvania ... she can’t make the argument she’s won the big states, the swing states.”

Through the Mississippi primary on Tuesday, Obama has 1,585 delegates to 1,473 for Clinton. It takes 2,025 to win the nomination.

U.S. Sen. John McCain of Arizona already has secured the Republican nod.

Early in the year, state lawmakers wrestled with the idea of moving the primary forward into early February to give voters more of a say in the presidential election process. But concerns about cost and the impact the quick timetable would have on local campaigns stymied the idea.

As it turns out, keeping the primary in April heightened its significance, at least for Democrats.

The only other times in the past quarter century when a nomination wasn’t decided before Pennsylvanians voted were the 1980 race between Carter and Kennedy and the 1984 campaign between Sens. Gary Hart and Walter Mondale, experts said.

“One of the reasons it seems important to us is it’s the first time in modern political times that Pennsylvania gets to participate when it’s still an open question,” said Gwen Torges, assistant political science professor at Indiana University of Pennsylvania.