Democratic Congressional candidate Judy Feder at a Joe Biden Rally in Loudoun County, Virginia

It wasn’t supposed to be like this.

This is the story of a Republican district gone wrong. This is the story of Virginia’s 10th Congressional District, which may very well flip to Obama next week, and could carry a Democrat to Congress.

Virginia’s 10th Congressional District was supposed to be a Republican’s paradise. Stretching from the upper Shenandoah Valley where Democrats are as sparse as three dollar bills into exurban Loudoun County, the Republican majority in VA-10 was a carefully crafted blend of rural social conservatives, and SUV-driving exurbanites who left their huge homes every Sunday for their evangelical church. It was the archetypal exurban district in which Karl Rove and the Bush Republicans planted their flag and sailed to victory.

In the east was Fairfax County, a behemoth standing at over a million souls total, whose western part and Potomac River shoreline was placed in the 10th, making up around a third of the district. To the west, Loudoun County, containing John Foster Dulles International Airport, vast acres of farms, and small towns like Purcellville and Leesburg beckoned Republicans. And further to the west, rural Virginia, “real Virginia” in their eyes, stretched until the elevation signaled the beginning of the Mountaineer State.

George Bush carried the district in 2004 with 55% of the vote. Times were good. Sellers were able to get more than their asking price as buyers trampled over any lot with a fresh “For Sale” sign, eager to sign their kids up for great schools and a quiet suburban life. Home equity sloshed around like water in an ocean, and developers had a field day plowing under fields of suddenly valuable land. Up sprouted subdivisions, vinyl-sided mushrooms proliferating across the hills. Incumbent Rep. Frank Wolf, a Republican, burnished himself as a moderate to appeal to suburbanites pleased with President Bush. Fairfax County became fabulously wealthy as lucrative high-tech jobs and cushy government work, combined with defense contractors galore, pushed the county’s median income even past fabled Orange County, California. Soon, Loudoun County would even outpace Fairfax. Kids were sent to some of the best schools in the nation as their parents raked in the dough.

Good times, unfortunately, don’t last forever. With development came traffic jams of epic proportions, and the specter of illegal immigration began to scare voters into whispers that soon grew thunderous. Gang activity was on the uptick. The war in Iraq dragged on, and gas prices took a toll on car-dependent voters. Housing values seemed almost to wobble in their inexorable rise.

Meanwhile for the Republicans, the flood of new residents into their paradise was nothing short of alarming. What started as a wave of like-minded exurbanites became a flood of diverse, less socially conservative, well-educated voters that were predisposed against typical Republican politics. Corruption on Capitol Hill might have manifested itself as a blurry vision of Jack Abramoff and his fedora, but for 10th District voters, the mess in Washington was just a quick (or, during rush hour, aggravatingly slow) ride down the Dulles Toll Road. Judy Feder, dean of the school of public policy at nearby Georgetown University, took on the challenge of unseating longtime incumbent Frank Wolf, who had represented the 10th even since the days when the district included liberal oasis Arlington County. Jim Webb carried the district by a razor-thin margin.

It wasn’t to be–Feder was to fall well short, even if she was well-funded, but the march of demographics went on.

Demography, as it is said, is destiny.

You see, the demographic winds that had created modern Loudoun County–torrid growth, the rapid exurbanization, a white-hot real estate market attracting the right kind of people–began to undo the Republican majority it helped create.

Any county is bound to be in flux if it grew by double-digits every year in population. Meanwhile, years of freewheeling dealing with developers led to an FBI probe leading up to the Board of Supervisors. Local Republicans descended into a civil war, retreating to firebomb issues like gay marriage and especially illegal immigration (in all this talk of Loudoun, don’t forget that Manassas, the epicenter of the anti-immigration backlash, is included in the 10th too).

Gas prices rising to dizzying heights pinched the pockets of even the most well-off suburbanites, who were exclusively dependent on their gas guzzlers. Then the roof began to come down, as foreclosures proliferated, taking out house after house in an epidemic of bad mortgages. No longer concerned with the politics of the Religious Rights, voters tired of corruption and wary of the economic house crashing down, suburban and exurban voters were hungry for change.

Then came Barack Obama.

Barack Obama pleased the suburban families who were hungry for change–but not just any change. Barack Obama was immensely popular in Fairfax and Loudoun counties, and as the Republicans in the 10th District became engulfed in scandal, Democrats looked increasingly good. Obama is rolling up huge leads in Fairfax and Loudoun, and Democrats are nearly certain to win Virginia’s 11th District to the southeast, a similar district with a similar congressman.

Like Frank Wolf, Tom Davis styled himself a moderate who represented well-off, government-savvy voters. Davis saw the writing on the wall, and announced that he was not seeking re-election in 2008. Since then, Davis has been engaging with a nasty breakup with the Republican Party, lambasting them for their treatment of moderates.

All that population growth translated into surges of new voters that don’t remember how long Frank Wolf has been in Congress. Since 2004, voter registrations are up an astonishing 25% in Loudoun County. With Republicans in full-fledged retreat, Judy Feder stands an outside chance of wresting away what once was the safest of seats. Below is the astonishing pace of voter registration growth, by county:

Let’s approximate what Judy Feder will need. Cut the district in half–Fairfax and Loudoun counties as the East, the rest as the West. With the East making up about 65% of the district, below is a rough approximation of what she needs to make a winning combination:

She will need massive coattails from Barack Obama. With roughly 65% of the district in Fairfax and Loudoun Counties, she absolutely must win there. Barack Obama is likely to win in that area with with double-digit margins, and new voters may be less likely to vote for the guy who’s always been there, because they’ haven’t been. Feder carried only 43% of the vote in the East two years ago with Webb at the top of the ticket, running about 10 points behind his performance. With Obama running up the score, she can and has a good shot at racking up the needed margins here. In the rest of the district, Judy Feder must stem the bleeding, and at least match her 2006 performance, where she garnered 36% of the vote. If Feder can follow the massive suburban wave for Obama and win the East with 55% of the vote, she will only need to hold down 40% in the rest of the district.

It will be tough–but if Barack Obama can pull off the massive wave in suburban counties, Judy Feder may very well sneak into office.