It was Sept. 17, 2009, and Virginia’s widely watched gubernatorial election had come to Tysons Corner. The contest was close, and Republican Bob McDonnell and Democrat Creigh Deeds were meeting in their second debate — an encounter that would prove decisive in the race. Northern Virginia’s business and civic elites assembled for the event under the auspices of the influential Fairfax County Chamber of Commerce.

The audience was fairly reflective of the prosperous, vote-rich region: largely unconcerned with partisan preoccupations, ethnically diverse, right-leaning on business matters, moderate-to-liberal on cultural questions, in a near-constant state of agitation over traffic congestion, and — after eight months of one-party control across the Potomac — deeply troubled by the specter of unbridled federal spending, debt, and economic interventionism.

Deeds came to the suburban face-off encumbered by a rough-hewn style better suited to his rural legislative constituency but armed with the influential support of the Washington Post. Its endorsement had catapulted him from likely also-ran to runaway winner in the springtime Democratic primary, and its sleuthing had turned up McDonnell’s provocative graduate-school thesis on social issues. Once unearthed in late August, the Republican’s 20-year-old handiwork at Pat Robertson’s Regent University had become the focus of a massive TV-ad assault by Deeds and his Democratic allies. The Post had deployed its powerful megaphone unrelentingly on Deeds’s behalf, with a volume of thesis-related news and opinion pieces barely surpassed by the paper’s coverage of the raging health-care and Afghanistan debates.

McDonnell, in whose campaign councils I participated, arrived on September 17 with a rare combination of personal and political assets. Having grown up in Northern Virginia, he claimed a special connection with the region and looked the suburban part. He had lavished attention on its main business organizations, including the Fairfax Chamber, during his years as a statewide candidate and attorney general. He also had reached out to the region’s varied ethnic communities, earning goodwill and separating his candidacy from the damaged GOP brand. An endorsement by Sheila Johnson, a billionaire businesswoman and top Democratic donor, had demonstrated McDonnell’s unusual cross-party appeal.

The Republican was in sync with the economic focus of the audience and the electorate. From his campaign’s start, McDonnell had stressed his resolve to be a “jobs governor” and had stayed on message, offering a steady stream of policy ideas to achieve that end. He also had put forward a detailed transportation plan that, while controversial in some particulars, demonstrated his commitment to the issue.

Perhaps most important, McDonnell and his Fairfax Chamber audience shared a disdain for the Democratic agenda in D.C. — from trillion-dollar deficits and government-managed health care to cap-and-trade energy taxes and special dispensations for organized labor. Nowhere in the state were congressional liberals’ efforts to remake America being watched more closely than in Northern Virginia, where national politics is local news.

As the debate unfolded, the candidates’ contrasting styles were on display — to McDonnell’s benefit. And three substantive developments would set the contours of the race for its final seven weeks, guaranteeing a landslide win for the Republican.

First, Deeds showed ambivalence about President Obama. Given the alarm over the president’s policy agenda among independent voters, Deeds’s reluctance to embrace Obama was understandable. But the cold shoulder he gave the president ticked off the White House and doomed Deeds to continued indifference among the Democratic base.

Second, Deeds persisted in pounding McDonnell for his decades-old thesis well after voters had tired of the issue. Though packed with moderates and women, the Fairfax Chamber audience responded with audible groans and some catcalls as Deeds repeated his familiar attacks. Missing that signal, Deeds and his handlers continued to spend millions in a vain attempt to define McDonnell as a loathsome culture warrior hostile to women’s aspirations. But the attack’s chief effect was to brand Deeds, not McDonnell: It gave the Democrat a strikingly negative image and suggested he was oblivious to voters’ concerns about the economy.

Third, Deeds fumbled on the question of taxes, setting in motion a string of events that left him on record as supporting $1 billion in new state taxes during a recession. During the September 17 encounter and post-debate interviews, Deeds bobbed and weaved on his tax plans. The Post, having previously praised the state senator for “courageously” voting to raise the gas tax, editorially signaled its chagrin and pressed Deeds to clarify. Boxed in by his powerful ally, the Democratic candidate dutifully declared his intentions, prompting a satisfied Post to proclaim that Deeds now had “unequivocally committed himself to support higher taxes.” Over the next six weeks, that quotation would appear in several million dollars’ worth of devastating ads by McDonnell and his supporters.

Following the debate, McDonnell continued to emphasize new policy ideas, prompting one supportive editorial page (that of the Fredericksburg Free Lance-Star) to crack that he had “a detailed plan for everything short of setting out your azaleas and flossing.” More significant, he continued to remind Virginia’s all-important independent voters of the national Democrats’ job-killing agenda. Deeds’s billion-dollar tax hike and primary-season utterances had more than established his link to the worrisome tax-spend-borrow spectacle across the Potomac.

Remarkably little of note happened in the campaign’s final three fortnights — except the defection of Democratic former governor Doug Wilder, who pointedly declined to endorse Deeds more than a month before the election. The race turned into a rout of the entire Democratic ticket — facilitated, surprisingly, by the White House, which responded to its first taste of electoral adversity by anonymously trashing Deeds and his campaign two weeks before Election Day.

Even for hyper-competitive Virginia, where tables historically have turned quickly, the political reversal this year was stunning. The top-to-bottom GOP victories suggest that major forces, not modest influences, were at work.

For most of this decade, the Mark Warner–led Virginia Democrats have won in the state by denying tax-hike plans, downplaying polarizing social topics, and talking up bipartisan solutions on quality-of-life issues. Deeds trumpeted Warner’s endorsement but rejected his approach on taxes and social issues, and it was Republican McDonnell who continually stressed his success as a bipartisan problem-solver. He impressively reestablished the broad center-right coalition that George Allen had assembled 16 years earlier and sustained through a string of GOP electoral and legislative wins in the 1990s.

The national scene contributed mightily to this year’s transformation. Less than a year after Obama captured independent support and the state’s electoral votes by capitalizing on Bush fatigue and economic unease, the sweeping agenda of the new president and his congressional allies had become the issue. Independent voters, who routinely decide elections in evenly divided Virginia, took flight in droves. And the “intensity gap” between the two parties, a factor in many off-year elections, was more pronounced than ever: Republicans were hungry and active; Democrats, sated and lethargic.

The irony was palpable. In the wake of the Democrats’ historic national triumph, Deeds faced the same dilemma that had confounded Republicans during the waning Bush 43 presidency. If he embraced the president to energize his Democratic base, Deeds would stoke the ire of independent voters, who found so much to fear in the one-party domination and liberal activism of Obama’s Washington. That dilemma seems likely to dog the Democrats in the 2010 midterm elections, since Virginia’s ideologically balanced electorate is more or less a microcosm of the country’s.

But if Republicans hope to re-create the magic that produced the GOP landslide in Virginia, they will have to study the ways of the candidate who made it possible. Atmospherics account for only so much in politics. Each election is still a choice between contrasting visions and policies. And the McDonnell candidacy represented a near-perfect match of man, mission, and moment.

McDonnell’s first and most important strategic decision was to reject the false choice, routinely debated in GOP and conservative circles these days, between standing on issues that resonate with the conservative base and broadening one’s appeal to moderate and independent voters. Both are crucial.

Since there are not enough Republicans and conservatives in a competitive state like Virginia to win with base support alone, the appeal to independent voters is a mathematical necessity. McDonnell never wavered from his conservative positions on life, the Second Amendment, property rights, and federalism, but he broadened the discussion to include issues on which conservatives and moderates agree — notably, the need for job-creating policies on taxes, spending, regulation, and labor. He was aided immeasurably by — and in turn reinforced — the reemergence of a clear partisan divide on these foundational economic and fiscal issues.

McDonnell also applied his principles — individual liberty, limited government, free enterprise — creatively to the solution of practical problems that motivate non-partisan voters. His transportation plan stressed innovative ways to deploy private capital and user fees in infrastructure development. His ideas on education emphasized choice, efficiency, and incentives for performance. His proposals for affordable new pathways to college degrees in science, technology, engineering, and math offered a vision of opportunity. His energy plan was comprehensive and entrepreneurial.

Tone was crucial, too. McDonnell eschewed the kind of polarizing rhetoric that turns off independent voters. He was unfailingly upbeat, respectful, and welcoming in his pronouncements, and was dignified and polished in his performances. This persona was not contrived, but rather reflected attributes McDonnell had exhibited throughout his public career.

A final factor of note is the quality of the campaign team McDonnell assembled. They understood and respected the candidate (not always true in campaigns) and mirrored McDonnell’s focus and discipline. Their efforts were aided immeasurably by state and national party organizations. A rejuvenated Virginia Republican party was a constant thorn in Democrats’ sides; the Republican National Committee and the Republican Governors Association countered Deeds’s generous financial support from organized labor and gave helpful advice while resisting the temptation to dictate tactics.

Every campaign is different, and transplanting a strategic model from one to another is perilous. But McDonnell won resoundingly in a competitive state that a year earlier had given Barack Obama an easy victory. Since no one else in the country has accomplished that feat yet, it is probably worthy of serious attention.