Upper Dublin, Pa. ? Last April, on the eve of the Pennsylvania primary, voters in this Philadelphia suburb were finding plenty of fault with both Barack Obama and John McCain. Many were preparing to – and soon did – vote for Hillary Clinton, helping her to a decisive victory in Pennsylvania.

This week, those voters are part of a mass movement to Obama, driven by much greater familiarity with the Illinois senator’s views, and a pronounced distaste for McCain and running mate Sarah Palin.

The striking shift in Montgomery County, often a bellwether, makes McCain’s task of recapturing Pennsylvania from the Democrats look almost like Mission Impossible.

Robert Stutz, a recently retired hospital administrator, was, like many of his neighbors, skeptical of both the eventual nominees when they were on the primary ballot, “so I was mostly listening to Hillary at that point.”

But he’s been impressed with Obama’s health care plan and says that McCain virtually disqualified himself with his vice presidential choice. “I can’t imagine putting Sarah Palin in a position to be president of the United States,” he said.

Rich Miles, a building maintenance man, answered the question about his voting plans with the words: “Not Obama.” McCain and Palin reflect his values, he said. “They put the country first.”

Whatever Palin may have done in shoring up the Republican base and securing the support of people like Miles, she clearly has cost McCain votes among some well-educated suburbanites.

Ann Marie Cutler, another Clinton primary voter, admits that she still has “some doubts about Obama in terms of experience,” but is reassured by the fact that “he’s very bright.” She watched the vice presidential debate and was “sorely disappointed” with Palin. She “drops her g’s constantly,” Cutler said.

Said Marjorie Lukens, a registered Republican: “The thought of Sarah Palin being a heartbeat away is terrifying.”

What has changed since last spring in this suburb is both the worldview and the impression of the candidates. Back then, the economy was not a major worry and opinion was divided between McCain’s stay-the-course policy in Iraq and the Democrats’ withdrawal plans.

Now, economic anxieties are pervasive and Obama, whose ads are seen far more frequently than McCain’s, is viewed as the candidate more seriously addressing those domestic problems.

Peter Wilde, a retired high school teacher who was working on his car on a sunny afternoon, said he has decided on Obama, but “I really like John McCain, and in any other election but this one, I’d vote for him. He’s a man of integrity and he speaks his mind.”

So, why Obama? “I think his tax plan is better for people like me, and after the last two weeks, my 401(k) is not in too good a shape.”

Lois Coar, the mother of two grown children, supported Mitt Romney earlier this year and is undecided for November. She cannot see voting for Obama – “not because he’s black, but I just can’t put it in words.” She likes McCain as a person, but “I can’t understand why he keeps talking about this Ayers guy” – William Ayers, the 1960s radical who became an occasional colleague and supporter of Obama in Chicago. “He should be focusing on the economy and real terrorists; that’s what people worry about,” she said.

If McCain is losing potential votes for such reasons, Obama seems to have harnessed all the enthusiasm of his converted supporters. Yoga instructor George Cordantz, a Clinton supporter “right up till the convention,” said, “I can’t wait to vote for him. These last eight years have been terrible.”

Debra Almack, an accountant and registered Republican, supported Mike Huckabee because “he is a person of character, not a politician.” After reading Obama’s memoir, “Dreams from My Father,” she decided he too “has a lot of character. I know he has some liberal ideas, but I really think he’s pragmatic.”

At the time of the primary, Obama was fighting two foes: Clinton and the voters’ lack of familiarity with him. The Democratic National Convention and those ubiquitous ads have dealt with the latter problem, and Clinton herself was working the Philadelphia suburbs on behalf of Obama on Monday.

In early September, Obama opened a storefront headquarters not far from the library where I was interviewing voters – one of three such offices in Montgomery County alone. The day after I visited, a platoon of New York volunteers was arriving to help local supporters canvass the same neighborhoods.

It’s hard to see how John McCain can overcome these odds in Pennsylvania.