There's the battle for Pennsylvania votes, and then there's the battle to shape the perceptions of what those votes mean.

The Democratic presidential candidates are struggling over perceptions as well as votes as they move to the next phase of their long-running campaign. The Pennsylvania primary, six weeks away, is at the center of competing definitions of just what that phase is.

In the Clinton campaign's description, Pennsylvania is a climactic showdown that will test the big-state appeal essential for victory in November. For the Obama campaign, the state is one more chapter in a delegate-selection story that makes sense only when read to its conclusion.

The dispute is rooted in hard numbers. After winning the popular vote in a string of big states, New York Sen. Hillary Rodham Clinton is the early favorite in Pennsylvania. With more victories overall -- Wyoming and Mississippi the latest among them -- Illinois Sen. Barack Obama has a delegate lead that appears certain to survive any likely Pennsylvania result.

Obama campaign manager David Plouffe did his best to manage expectations for the Pennsylvania contest in a conference call yesterday, in which he called Mrs. Clinton "the prohibitive favorite" in the Keystone State.

"Now that Mississippi is behind us, we move on to the next 10 contests," Mr. Plouffe said in a memo that amplified his depiction of the race's current status. "The Clinton campaign would like to focus your attention only on Pennsylvania -- a state in which they have already declared they are 'unbeatable.' But Pennsylvania is only one of 10 remaining contests."

The Clinton campaign seized on the remarks as evidence that the Obama campaign planned to give the state short shrift. "Pennsylvania is of particular importance -- along with Ohio, Florida and Michigan -- because it's dominated by swing voters, who are critical to a Democratic victory in November," the Clinton campaign said in its own memo distributed yesterday. "... But the Obama campaign has just announced that it is turning its attention away from Pennsylvania."

An Obama spokesman dismissed the suggestion that the Illinois senator planned to concede the state to Mrs. Clinton. "It's absolutely important to us," said Sean Smith. "It's a big, meaningful state, and we're going to do our best to do well. The point of the [Plouffe] call was just that it's not the final Armageddon that Clinton wants to make it out to be."

The opening days of the Pennsylvania campaign offered an early contrast between the two campaigns in the pace of appearances. Mrs. Clinton flew into the state with major rallies, each attended by thousands, in Scranton, Harrisburg and Philadelphia. Her husband, former President Bill Clinton, made multiple appearances across the state, as did their daughter, Chelsea. Mrs. Clinton is expected in Pittsburgh tomorrow for campaign events that day and a stop at the St. Patrick's Day parade Saturday.

Mr. Obama's initial campaign swing consisted of a low-key visit to a wind energy plant in Bucks County, alongside a round of interviews with Pennsylvania reporters. He was to meet Western Pennsylvania voters during an appearance today at Penn State's Beaver campus, but that event was cancelled because he had to be Washington for key Senate votes. After the cancellation, his next scheduled campaign appearance was to be this weekend in Indiana, one of the handful of states that will vote after Pennsylvania.

But Mr. Smith cautioned against drawing conclusions from the first few days of what will be the longest focus on any state since the presidential race left Iowa. "I think you are going to see Senator Obama spending the most precious resource the campaign has -- his time," he said. "There are plans for him to be back. We are already up on radio. We're doing what campaigns do. It's just a fact that Clinton starts off this campaign with advantages in Pennsylvania."

The argument over the significance of the next primary is a subset of the two campaigns' broader struggle to shape perceptions of the results so far. Mr. Obama has a modest but seemingly insurmountable lead among the delegates elected by primary and caucus voters. Mrs. Clinton's campaign has won fewer states, but virtually all of the larger ones, except for Mr. Obama's Illinois home.

That record, the Clinton campaign maintains, makes her a better bet to carry the big-state troves of electoral votes that will determine the general election winner.

The Obama campaign counters that its ability to pick up delegates in a wider variety of states shows his general election strength, because it rests in part on his success in attracting the votes of independents and even some Republicans -- the kind of votes that will determine the outcomes in the November battlegrounds. Mrs. Clinton's successes in the larger states, the Obama forces contend, is rooted in her appeal to base Democratic voters, who will end up supporting any Democratic nominee.

The crucial audience for this debate is the superdelegates who have the power to resolve the Democratic nomination, as neither contender appears to be within reach of a convention majority on the strength of elected delegates alone.

Mrs. Clinton leads in the support of superdelegates, but her advantage has eroded in recent weeks. Mr. Obama has had greater success in winning new commitments from the party and elected officials who are free to switch their preferences at any time before the call of the roll of states in Denver.

Yesterday's Clinton campaign memo emphasized the importance of Florida and Michigan, along with Pennsylvania, as tests of the candidates' big-state appeal. The focus was part of an ongoing Clinton effort to shake up the current delegate dynamics by seating the currently banned delegations of those two earlier-voting states.

Their results were barred by Democratic National Committee rules because the states violated the party's calendar in scheduling their primaries. While all of the Democrats honored a pledge not to campaign in the sanctioned states, Mrs. Clinton won both, although she was the only major Democrat with a slate of delegates on the Michigan ballot.

"In my view, there are two options -- honor the results or hold new primary elections. I don't see any other solutions that are fair and honor the commitment that 2.5 million voters made in the Democratic primaries in those two states," Mrs. Clinton told the Associated Press yesterday.

According to the AP, Mr. Obama said his campaign is in touch with Democratic officials in the two states, and that he expects some accord on seating them. "My bottom line is, I do want to make sure that the Florida and Michigan delegations have an opportunity to participate in the convention," he said. "And we want to figure out an equitable way to do that."

While some Florida Democrats want the results of the state's first banned primary to stand, there appeared to be some progress yesterday toward a new, mail-in primary that might be held sometime in June.

Some analysts have projected that even the inclusion of Florida and Michigan results, and of Clinton victories there, would be unlikely to overturn Mr. Obama's pledged delegate lead. But the New York senator's hope is that wins there, as well as in Pennsylvania, might narrow the gap enough to sway the perceptions and, with them, the votes of the superdelegates.