Some other analysts were more cautious in saying Pennsylvania has dropped from the ranks of Ohio, Florida, and other swing states.
"We still have a Republican governor, a Republican legislature, and a congressional delegation that is overwhelmingly Republican," said Marcel Groen, Democratic chairman of Montgomery County.
Groen said future elections might depend on who the Republican candidate was. "If it's Chris Christie," he asked, "don't you think Pennsylvania is a swing state?"
President Obama's victory margin here, compared with 2008, was cut in half. He still coasted to a 52 percent win and a margin of 5.2 points over Romney and two minor-party candidates.
Obama won 12 of 67 counties, but gained a 465,000-vote majority in Philadelphia and a 119,000 majority in the four suburban counties. The region gave him 43 percent of his 2.9 million votes.
With a one-million edge in registered voters, Democrats also took all four statewide offices on the ballot - led by the easy victory of U.S. Sen. Bob Casey for a second term, and the emergence of Kathleen Kane as a Democratic star with her even-easier triumph as attorney general.
Rick Bloomingdale, president of the state AFL-CIO, said he was especially pleased with Casey's thumping of Republican Tom Smith.
"Bob Casey ran on an agenda of doing what's right for the middle class," he said. "Tom Smith spent $20 million of his own money to go against that message."
Republicans, however, won 13 of 18 House seats and retained solid control of both the state House and Senate.
Analysts stressed the difference between a presidential election year and any other year in the four-year political cycle, especially in Pennsylvania.
A presidential election can bring massive voter turnout in Philadelphia, sweeping away Republican margins elsewhere.
In the last two decades, Philadelphia's four suburban counties have swung toward the Democrats. Obama won all four in 2008. He came close to doing so again this year, but fell 1,800 votes short in Chester County.
"We have a difficult time in these major presidential election years," said Republican State Chairman Robert A. Gleason Jr. of Johnstown.
"We lost Philadelphia and [the four suburban counties] by 569,000 votes. That's a big hole to dig out of."
Some national Republicans suggested that Romney lost because he wasn't a true conservative and didn't excite the GOP electorate. Gleason said his party needed more moderation, not less.
"To win presidential elections, you have to be in the mainstream," he said. "We didn't win young people. We didn't win young women. We didn't win African Americans. We didn't win Hispanics. . . . We need to make those groups feel good about the Republican Party and our solutions."
James Burn Jr., the Democratic state chairman, from Pittsburgh, said he could not foresee a Republican win for president here in the near future.
"Pennsylvania is not a swing state," he said. "It hasn't been for some time. What we saw was exactly what we have seen from Republicans going back to 1992."
Adam Geller, a Republican pollster who worked on Pennsylvania surveys as part of a bipartisan team for The Inquirer, thinks that Republicans can have a chance in the future - and that Romney might have had one if he'd started earlier with TV ads.
"Had they started in mid-September," he said, "we might be looking at a different result now."
Pollster G. Terry Madonna of Franklin and Marshall College said he would not write off Pennsylvania as a battleground state.
"We could become a battleground under the right circumstances," he said. "It is not completely out of the question. . . . But history is not on [the Republicans'] side."
Madonna said Democrats also made gains for the future Tuesday. Besides the wins by Casey and Kane - both from Scranton - Robert McCord of Montgomery County was reelected as state treasurer and Eugene DePasquale of York County was elected auditor general.
Pennsylvania's governors and U.S. senators often come from these ranks, Madonna said. That gives the party "a strong bench."
Democrats were disappointed to see U.S. Rep. Mark Critz go down to Republican Keith Rothfus in the 12th House District in Western Pennsylvania.
The other 17 congressional races were pretty much noncompetitive - the result of post-census redistricting by the Republican-controlled Legislature to protect incumbents.
Only one challenger, Democrat Kathy Boockvar of Bucks County, put up a real fight. And she ended up losing to Republican Rep. Mike Fitzpatrick in the Eighth District by 13.4 points.
U.S. Rep. Bob Brady, the Philadelphia Democratic chairman who won his ninth House election, said redistricting worked for Democratic incumbents, too.
He said Republicans had to push Democratic voters somewhere, so they pushed them into already Democratic districts.
Allyson Y. Schwartz, in the once-competitive 13th District, in Montgomery County and Philadelphia, won by a ratio of 69-31 over Republican Joseph James Rooney. Brady won by a ratio of 85-15 over Republican nominee John Featherman.
It was the top-of-the-ticket that set the mood when Gov. Corbett and other Pennsylvania Republican leaders held a "Romney/Ryan Election Night Celebration" Tuesday at the Harrisburg Hilton.
Just before midnight, 30 of the party faithful stood around a mostly empty ballroom as a band played the Journey hit "Don't Stop Believing" and watched grimly as cable news showed state after state dropping into the Obama column. They were awaiting the word from their state party leaders, who were locked away in the nearby "war room."
At last they emerged - Gleason, national committeeman Bob Asher, and Corbett - too late for any local TV news shows to broadcast their remarks live.
Said Corbett: "This is not exactly the way that we wanted it to turn out. There is a one million registration deficit. We will have to change that."
Asher was keeping the faith at the lectern.
"Tonight, we lost. We've lost in the past in Pennsylvania," he said. "We have to get up, dust ourselves off, and come out fighting."
Contact Tom Infield
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Inquirer staff writer Amy Worden contributed to this article.