The voters on the single, long, twisting block of Deerwatch Drive in western Fairfax County are almost never wrong.

Since their Walney Village development was built in 1999, their neighborhood just south of Dulles airport has picked almost all winners, regardless of political party.

This year, many of those who live in the alternating brick and siding townhouses, each with a tiny patch of grass out back, are frustrated and confused as another election looms. They’ve watched as one Washington standoff after another injected needless uncertainty into their lives, especially since many of them work for the federal government or for defense, medical and high-tech contractors in the Dulles corridor. They’ve seen the value of their three-bedroom houses tumble by 10 to 20 percent, down to about $300,000. Many couples cobble together six-figure incomes, but still end up short each month.

The families here reflect Virginia’s — and the nation’s — new demographics compressed into a single block: white and black, Hispanic and Asian, Kims and Les, Vargases and Sims, Millers and Kashanis.

They are at the core of this fall’s presidential battleground — a suburb made up of exactly the kind of sporadic voters who put Barack Obama over the top last time. But Deerwatch Drive is also a place where fiscal conservatives do well, where the recession hit hard and the recovery feels anemic.

Rick Santorum (Joe Ciardello)

Deerwatch by day is mostly empty, with just a few young mothers and retirees around. But starting at about 3:45 each afternoon, a trickle of workers driving home grows into a steady stream. By sunset, darkened windows glow amber and smells of cooking chicken and onions drift into the street.

Eric Vandagriff, a 25-year-old paramedic, ordinarily isn’t much for politics, but he’s been paying attention lately and the simplistic promises he hears from both parties sound like a joke, he says, and neither party is leveling with voters about the economic pain that lies ahead.

Vandagriff, who shares a townhouse with two friends, glumly describes his vote for Obama four years ago like this: “I bandwagoned. I was looking for change.” He’s determined not to make that mistake again. But if all the Republicans have to offer is Mitt Romney — “he’s pompous, he’s got a superiority complex” — Vandagriff’s not sure what he’ll do. Maybe stay home.

Just across the street is Matt Erbe, a 45-year-old federal worker and lifelong Republican. His mortgage is underwater, his pay’s been frozen for two years and he’s so fed up with the president that he’s considering putting an upside-down Obama bumper sticker on his car — a signal of distress.

But hold on: Erbe says the party most responsible for the nation’s budget mess is his own — and Republican bashing of federal workers grates at him: “Look, we’re trying to do a decent job, and nobody’s getting rich off this work.” The GOP candidates leave him cold. “Mitt Romney acts like he’s going to fly over my house in a Learjet,” says Erbe, who voted for John McCain four years ago. Bottom line: He’s leaning toward Obama.

Little excitement for candidates

The whole mess — the budget battles, the stalemates and name-calling on Capitol Hill, the obvious deep structural flaws in the nation’s economy — have all played out in the lives of Deerwatch residents. It’s made many cynical and frustrated with politics.

The presidential candidates haven’t been here yet, but they might want to check out Deerwatch Drive because people around here know how to pick winners. The neighborhood chose Democrat Mark Warner for Senate, flipped from Democrat Timothy M. Kaine to Republican Robert F. McDonnell for governor, and selected George W. Bush for president twice. Four years ago, they erred, but just barely, choosing McCain over Obama by 15 votes.

Virginia Democrats, Republicans and independents alike look at Tuesday’s Republican primary in the state and ask what’s gone wrong with a political system that leaves only Romney and Ron Paul on the ballot (Virginia’s tough rules kept Newt Gingrich and Rick Santorum from qualifying.) On Deerwatch Drive, there’s precious little excitement about those choices, even among those who regret their 2008 vote for Obama.

Many wonder whether there’s any point in voting.

“Whether Obama wins will depend on whether he can reenergize those people who came out for him in ’08 — people who hadn’t been seen at the polls before and haven’t come out since,” says Ted Velkoff, a Chantilly Democrat who is on the county school board.

Of the 70 Deerwatch residents who voted in 2008, only 30 have taken part in any subsequent election, even those for governor or senator. Half of the ’08-only voters are either immigrants or children of immigrants, according to county records and Post reporting.

Come November, Deerwatch residents and people like them in suburbs all over Virginia will be the grand prize in a presidential contest that could turn on whether Obama can again motivate millions of young people, immigrants and minority voters who don’t usually vote.

Swing -state status

Thanks in large part to developments like Walney Village, once-solidly Republican Virginia has morphed into the quintessential swing state. Its U.S. Senate race features two legendary vote-winners, Kaine and Republican George Allen, both former governors, vying for the seat being vacated by Sen. James Webb, a conservative Democrat who ousted Allen six years ago.

Virginia’s journey from red to purple has been led by explosive growth in the Washington suburbs; three counties — Loudoun, Prince William and Fairfax — accounted for 40 percent of the state’s growth in this century’s first decade. Most of that growth has come from immigrants, Hispanics and Asians: Although Virginia’s under-18 population increased 7 percent between 2000 and 2010, the number of native-born white and black children actually declined, census data shows.

Asso Rashid — a civil engineer who came to the United States from Iraq for college, went home, and then returned 13 years ago — figures himself and his fellow Muslims on the block as natural Republicans. “We’re conservative people, in many ways,” he says. “Socially, our religion, fiscally. I like the Republican view on abortion.” He voted for McCain last time, though he liked Hillary Rodham Clinton too.

This time, Rashid plans to cast his ballot for the president, even though business has slowed a bit at the construction company where he works, even though his house is underwater, even though he thinks Obama hasn’t done much for the economy. Rashid will vote to reelect Obama because “I get an anti-immigrant feeling from Republicans. They don’t like foreigners. And it’s just not logical to vote for somebody who hates you.”

Similar circumstances led a software engineer up the block from Rashid to the opposite conclusion. The Pakistani immigrant, who spoke only on the condition of not being named because he works on classified projects for a military contractor, voted for Obama last time but won’t again.

“My paycheck is down almost 50 percent, and Obama didn’t discover the jobs problem until recently,” the engineer says. “I thought he was serious about getting out of Iraq and Afghanistan, but those wars just kept going and our American sons and daughters were losing their lives. Obama is a very moving speaker, but those speeches don’t buy food for my kids.”

Support and second-guesses

Stirring memories of Obama’s first campaign remain powerful, especially among black families on Deerwatch. They refuse to blame Obama for an economic mess he inherited or for a stalemate they say Republicans in Congress created.

“For some reason, people expected President Obama to come in and wave a magic wand and make everything better,” says Georgia Roberts, an 80-year-old retired customer service worker. “These idiots blocked him every step of the way.”

But Roberts, who is black, sometimes wishes the president would be more forceful. “I talk back at the television, and I tell him to get really black and tell those people off, just bring it home,” she says. “He’s being this nice gentleman while the Republicans went on with this crazy stuff about his birth certificate.”

Roberts, a lifelong Democrat, will vote for Obama again, but worries that “there may not be the same kind of enthusiasm this time. I just wish the Republicans would realize they’re also supposed to be representing all of us, not just the very rich.”

Robert Thompson, who runs a small IT subcontracting firm out of his home, sees the pain the recession has inflicted on his neighbors. “We have a lot of Lamont Sanfords here, 32 and back home with the parents,” he says, referring to the underemployed son who moved in with his father on the 1970s TV sitcom “Sanford and Son.”

The downturn forced Thompson, 69, to lay off six of his 14 employees, but he’s back up to 10 now. “I got hit hard,” he says. “My house was underwater. But even in Grant Park on Election Night, Obama was saying this was going to require hard work and a long time. I still like the way he operates, like a silent assassin. He gets the facts and makes a determination, like the way he went after bin Laden, very quietly taking care of business.”

Thompson’s neighbor across the street is equally certain Obama has not been up to the job. “He didn’t have the experience,” says James Miller, a 56-year-old construction worker now helping to widen the Fairfax County Parkway. “If Barack Obama had been a white guy, he never would have got a second look.”

Miller, who is white, is leaning toward Romney because of his experience as a governor; he calls Obama a profligate spender — even on the construction projects that keep Miller solvent. “None of our jobs got stimulus money,” he says. “It’s all state work.” (Virginia’s transportation department says the Parkway project is paid for with federal stimulus money.)

Thuong Phan, a cashier at McDonald’s who is partly disabled and an immigrant from Vietnam, says he has seen direct benefits from Obama’s policies. Phan, 49, says he’s on three medications that Medicare didn’t used to cover but now does. He commutes on Interstate 66, where he says the ride is easier after stimulus-funded improvements. And as a cashier who deals with the public every day, he says, “I can see the irritation in people when they deal with me, and people are more relaxed now than when Bush was president.”

Such definitive positions are not the norm along Deerwatch Drive. More common is a sense of letdown from the high hopes Obama inspired four years ago. Connie Martin, a medical lab manager who went door to door for Obama last time, is 63 and as she gets older, she finds herself becoming more politically aware, which has led to a letdown.

It was the Sept. 11 attacks that woke her up politically. “I realized there were people out there that wanted to kill us, and there were things we were doing as a country that made people around the world angry at us.”

She expected Obama to pull the United States out of foreign wars and focus on problems at home. But she’s been disappointed. When she saw him push health care reform even as so many Americans were out of work, she questioned his priorities. She’ll vote for Obama again, if only because she sees nothing better in the Republicans.

Vandagriff feels deflated, too. Like many young people caught up in Obamamania four years ago, Vandagriff is still hunting for a candidate who can break through the fog of Washington and reverse the trend in which the rich seem to get richer while everyone else struggles. He thought about Paul for a time but doesn’t see the Texas congressman as a realistic alternative.

So he waits and watches, like the bartender a couple of doors up and the sign maker across the way. They don’t know each other, but they speak almost in unison about what they want from this campaign: someone who will break the deadlock in Washington, taking on the hard task of paying the bills and digging out of trouble, just like the people on Deerwatch Drive.