Speaking with reporters today, David Plouffe, Barack Obama's national campaign manager, touched on a number of subjects, including expectations for Pennsylvania, mail-in elections in Michigan and Florida, and accused the Clinton campaign of attempting to change the rules.

"They are the prohibitive favorite" in Pennsylvania, Plouffe said about the Clinton campaign, which he noted described itself as "unbeatable" in the state. "They should win by a healthy margin."

But Plouffe said the campaign "will not be defined by Pennsylvania." With eight states and two territories left on the Democratic primary calendar, Plouffe said the campaign views the next 10 races "collectively."

"We look at 566 pledged delegates left," he said. "We want to try and maintain our pledged delegate lead. Not only looking at Pennsylvania or North Carolina, but all of them. And we want to do as well as we can in all 10 of these contests so that by the end of June we remain the clear pledged delegate leader and clearly the strongest candidate to take on John McCain."

On seating the Michigan and Florida delegations at the Democratic convention, Plouffe said the campaign will wait to see what plan the Democratic Party comes up with, and that both campaigns would need to follow whatever the new plan may be. He said the campaign has "real deep concerns" about a mail-in election, and that "the easiest solution here would be some kind of fair seating of the delegations that is not reflective of those contests in January," so that Clinton is not "unfairly" advantaged. "We were not even on the ballot in Michigan and we weren't campaigning in Florida," he said.

Plouffe said the Clinton campaign is attempting to change the DNC rules that she once agreed to. "Clinton herself, on October 11 of last year said that, 'You know it's clear this election they're having isn't going to count for anything.' So Senator Clinton said she was playing by the rules. Now when it's serving her political interests, they're trying to change the rules. We think that's the kind of political maneuvering and calculation that voters are tired of."

Later in the conference call, Plouffe said, "We do not think that the Clinton campaign's approach here is based on benevolence toward Florida and Michigan. It's based on increasingly desperate, self-serving stretching for whatever they think can help them win the nomination."

According to the RCP Popular Vote Totals, Obama is leading Clinton by about 700,000 votes, without counting Florida and Michigan, or a few caucus states. Plouffe noted that if one were to count those caucuses that have not reported popular vote totals, including Nevada, Washington, Maine and Iowa, Obama's lead would be about 1 million.