The poll's margin represents a net swing of 2 percentage points in Romney's favor since the last Inquirer survey, which found the president ahead 50 percent to 42 percent in the first week of October.
In the last three weeks, Romney has pulled into a narrow lead in several national opinion polls, and is running even with, or in front of, Obama in surveys of some swing states.
Meanwhile, Pennsylvania has missed the brunt of the presidential campaign. The candidates barnstorm in, and pour hundreds of millions of advertising dollars into, the same nine battleground states: Colorado, Florida, Iowa, Nevada, New Hampshire, North Carolina, Ohio, Virginia, and Wisconsin.
Neither presidential campaign has advertised on Pennsylvania broadcast stations for months. The state has not been on Obama's travel schedule but for a pair of Philadelphia fund-raisers in June and a Pittsburgh event in July. Romney visited the Union League in Center City and Valley Forge on Sept. 28, the first time he had set foot in the state since mid-July - and also the last time he has.
Republican pollster Adam Geller, who helped conduct the Inquirer Pennsylvania Poll, said it spelled trouble for the president and an opportunity for the Romney campaign, because Obama is stuck below 50 percent support.
"I think the race is going to be neck-and-neck," said Geller, founder and chief executive officer of National Research Inc. "As we've seen nationally, the energy seems to be on the Republican side. . . . Both sides ought to be contesting the race more seriously than they are."
Jefrey Pollock, the president of the Democratic firm Global Strategies Group, disagreed, saying the president is in a good position as the clock winds down on the campaign.
"It would be hard for the Romney camp to close the gap in the time left to them," said Pollock, whose firm also conducted the survey. "Pennsylvania has been the great bridesmaid for a number of cycles for the Republicans, and I don't see the wedding taking place this time either."
George H.W. Bush was the last Republican to carry the state, in 1988. And the Inquirer survey found that 55 percent of likely voters view Obama favorably, while 43 percent have an unfavorable opinion of the president.
A majority of likely voters continues to approve of Obama's job performance - 53 percent, to 45 percent who disapprove - roughly the same ratio as in the three previous Inquirer polls.
"When a majority of people think somebody is doing a good job, they don't tend to fire them," Pollock said Friday in an interview.
Geller countered that "you can like Obama on a personal level and agree with him on a lot of issues, but you can also say that it's just time for a change."
Results of the Inquirer Pennsylvania Poll are based on live telephone interviews with 600 likely voters, conducted from Tuesday through Thursday, and subject to a margin of error of plus or minus 4 percentage points.
The poll gives Obama a wider margin than some other Pennsylvania surveys. The website RealClearPolitics puts Obama's average lead in recent polls here at 4.8 percent.
Obama's advantage among women was undiminished in Pennsylvania, according to The Inquirer's poll - even though surveys by the Associated Press and the Washington Post/ABC News last week found that Romney had narrowed the so-called gender gap nationally.
In Pennsylvania, Obama leads among women, 52 percent to 40 percent, The Inquirer's poll found. Romney has a slim advantage among men, 47 percent to 46 percent.
Claudia Utti, a registered Democrat who responded to The Inquirer's poll, said she plans to stick with Obama. She supports the health-care law and is convinced that the president is sincere.
"I would never vote for Mitt Romney - I can't stand him," Utti, 65, of Lafayette Hill in Montgomery County, said Friday in an interview. "We don't need another millionaire. People of that class don't have any idea how hard it is to work for a living."
Poll respondent Robert Goshey of Chester County represents the opposite view. To him, voting for Romney is "not a choice" but a duty in order to stop what Goshey calls Obama's antibusiness policies and inaction on the debt.
"I don't believe in redistributing income," said Goshey, 57, an engineer who lives in the Oxford area. "We need rich people - of which I am not one - to power the economy, and that makes us all better off even though the world is not perfectly fair." Romney's national momentum began after he trounced Obama in their first debate Oct. 3.
Yet after all three debates, 43 percent of likely voters in the Inquirer Pennsylvania Poll said they believed that Obama was the overall winner, to 39 percent who thought Romney was. Eight percent considered the debates a tie, and 10 percent said they did not know.
About three-fourths of likely Pennsylvania voters said they watched at least some of the final debate, televised from Boca Raton, Fla., on Monday night, including 43 percent who said they watched the whole thing.
That final debate was on foreign policy. Respondents in the Inquirer poll said Obama would do the better job of handling foreign policy for the next four years, 52 percent to 39 percent.
On Friday, one Republican group signaled it might launch an ad blitz in an effort to push Pennsylvania into Romney's column.
The group Americans for Job Security reserved at least $454,150 worth of airtime on Philadelphia broadcast stations and more than $200,000 worth of time on cable channels in the market, according to Federal Communications Commission reports and political sources that track ad spending.
That time could be used for spots aimed at attacking Obama or boosting Romney. Americans for Job Security had mostly supported GOP congressional candidates around the country until it threw itself into the presidential race in late September with an initial swing-state buy of $8.7 million.
Because it is organized as a trade association rather than a super PAC, the group is not required to disclose its donors. Americans for Job Security's website says: "Our members are businesses, business leaders and entrepreneurs from around the country. AJS does not disclose or discuss its membership further than this."
About the Polls
The Inquirer Pennsylvania and New Jersey Poll results are based on telephone interviews conducted Oct. 23-25 with 600 likely presidential-election voters in Pennsylvania and 601 in New Jersey.
Polls were conducted by a bipartisan team of national political pollsters - Jeffrey Plaut, founding partner of the Democratic firm Global Strategy Group, and Adam Geller, chief executive of the Republican firm National Research.
The estimated margin of error for statewide results is plus or minus 4 percentage points; for results of the five-county area - Bucks, Chester, Delaware, Montgomery, and Philadelphia Counties - the margin is plus or minus 6.9 percentage points. The Pennsylvania Poll is sponsored by Susquehanna Bank.
Results for the seven-county South Jersey area - Atlantic, Burlington, Camden, Cape May, Cumberland, Gloucester, and Salem Counties - have a margin of error of plus or minus 8.5 percentage points. The New Jersey Poll is sponsored by PSEG.
Coming This Week
What do voters think of the jobs Gov. Corbett and Mayor Nutter are doing? Also, Inquirer poll results in the race for attorney general in Pennsylvania and the New Jersey Senate race. We also ask what voters think of municipal consolidation in New Jersey.
What do Pennsylvania voters think about privatizing state liquor stores? How do New Jersey voters feel about alternative energy?
Contact Thomas Fitzgerald at 215-854-2718 or firstname.lastname@example.org, or follow @tomfitzgerald on Twitter. Read his blog, "Big Tent," at www.philly.com/BigTent.