One of the first stops on Sen. John F. Kerry's post-convention campaign buscapade was in Greensburg.

In this seat of a county with a Democratic registration edge of nearly 2-to-1, thousands of supporters lined the streets, undeterred by driving rain as they gathered to cheer the new Democratic nominee.

Westmoreland is a county heavily dominated by Democrats in municipal offices, as well. Its board of commissioners has a Democratic majority; its state House delegation is overwhelmingly Democratic.

So when President Bush traveled to Greensburg for a rally last week, "to ask for the vote," he might have seemed to be facing tough odds -- unless you looked at the county's recent statewide and national election totals.

Belying its registration statistics and political character at the local level, Westmoreland County over the last 15 years has become an increasingly reliable source of votes for Republican candidates. And reliance on that trend was one of the foundations of an aggressive GOP-controlled redistricting plan that dramatically reshaped the state's congressional map two years ago.

What this reflects is a drift of socially conservative voters away from the Democratic Party that presents a key challenge to Kerry and other Democratic candidates.

While former Vice President Al Gore won Pennsylvania by an unexpectedly strong margin of more than 200,000 votes four years ago, Bush carried this nominally Democratic county by nearly 10,000 votes. Republican Sen. Rick Santorum carried it by a similar margin over former Rep. Ron Klink, whose congressional district overlapped the county.

Two years later, Gov. Ed Rendell won the Pennsylvania governor's race in a landslide, sweeping many Republican counties in the eastern part of the state. But in Westmoreland, he lost by roughly 10,000 votes to former Attorney Gen. Mike Fisher.

"These are folks who are part of families who voted Democratic in my father's and grandfather's generations," said Santorum. "They watched the Democratic Party move away from them."

The issues of abortion and gun control are repeatedly cited by Republican and Democrats as among the keys to the GOP inroads in counties like Westmoreland across the western half of Pennsylvania.

"I don't think there is any question that there have been a combination of issues in that county that have had an impact on Democrats," said Auditor General Bob Casey, the only member of his party's statewide ticket who carried the county in 2000.

"Abortion is one issue. The right to bear arms is another," he said. "But I think taxes are still a huge issue in Western Pennsylvania and I think there is no question that the Republican Party in the last 25 years has put out a misleading but effective message that they are the anti-tax party."

Casey opposes abortion. The only other Democratic statewide candidate who came close to him in GOP opposition in the county in 2000 was Lt. Gov. Catherine Baker Knoll, who was then running for treasurer against incumbent Barbara Hafer, who is pro choice.

"This is a group that looks more at the person," said Rep. Tim Murphy, R-Upper St. Clair, of the county's voters. "Many of them moved out of Allegheny County. They are not as attached to a party as they are to issues."

Murphy's congressional district is part of a major GOP bet that the Republican gains of recent years in Westmoreland and other counties in southwestern Pennsylvania are more than transitory.

The redistricting that followed the 2000 census was completely controlled by the Republican Party. Santorum was among its key architects. He and his allies, over the objections of some more cautious Republicans in Harrisburg, pushed through a new congressional map that maximizes the opportunities for GOP-controlled seats in Western Pennsylvania. Another way to describe that strategy, however, is that it maximized the number of potentially competitive districts in the southwest rather than emphasizing the creation of completely safe Republican districts.

Shaped like a skewed bow tie, Murphy's 18th District extends from the Ohio border, narrowing south of Pittsburgh and spreading out again in the nominally Democratic communities of Westmoreland County. While the district as a whole still has a Democratic registration edge, Santorum and his allies bet that those communities would vote for a Republican at the congressional level, and they did.

Murphy said the disconnect between the two parties' performance at the local and state levels in Westmoreland County is rooted in tradition and community.

"In many of the boroughs and townships across the county, the Democrats have traditionally controlled local politics and there's a feeling that you have to be a Democrat to be involved in local politics," Murphy said. "I've had [local officials] say to me, 'I agree with you and the Republicans on the issues, but I had to run as a Democrat to win.' "

Santorum noted that his party has to contend with the opposite dynamic in some eastern suburban counties, where the GOP dominates local offices in counties that have become more hospitable to Democratic candidates at the statewide and national levels.

But in Western Pennsylvania's redistricting, he said, he was worried about counting on the votes of nominal Democrats.

It turned out, he said, that "they're returning to their roots because the Democratic Party is not going to return to them."

Rendell said one major challenge for Democrats in Westmoreland and similar counties is to defuse the power of gun control issues. He noted that Bill Clinton carried Westmoreland in 1996 in part because he argued to hunters that while he'd supported passage of the Brady Bill and the assault weapons ban in 1994, "since then, 500,000 felons have been denied gun permits and not one of you has lost a minute in the deer woods.' "

"That's the answer," Rendell said. "The NRA fills hunters' heads with all these visions that moderate gun safety measures and gun control will hurt their right to hunt. They say it often enough that it sticks. But Bill Clinton was able to say, look, this is what we did. They have to have evidence that you're not out to hurt hunting, which is a way of life."

Casey said that in the current political climate, the Kerry campaign could make headway with Westmoreland County's relatively older population by empathizing differences with the president on health care. Casey also argued that Kerry's status as a veteran would help him in the county, despite the assaults on his Vietnam War record by his Swift boat foes.

"One thing he can do that some Democrats have not been able to do in recent years is bring a message of strength as well as a message of hope," Casey contended.

Casey, a candidate for treasurer this year against Republican Jean Craige Pepper, said Westmoreland County exemplifies the challenges for Democrats not only in the presidential election but for the foreseeable future.

"These are counties that 15 years ago, or even 10 years ago, we could count on winning 55-45; now we're losing some of them 52-48. If our party cannot win counties like Westmoreland with more consistency, we're not going to win many races," Casey said.