Tea party challenger David Brat defeated the second-ranking Republican in the House, Majority Leader Eric Cantor (R-Va.). So, who is David Brat? Here he is, in his own words. (Jackie Kucinich/The Washington Post)

There are hundreds of reporters covering politics in Washington. Before Tuesday night, only a few of them paid any attention to the year’s biggest political story.

College professor Dave Brat’s defeat of House Majority Leader Eric Cantor in the Republican primary in their Richmond-area district stunned more than Cantor and the GOP establishment. Most of the national news media slept through the campaign, waking up only when the votes started coming in Tuesday.

The result: Perhaps not since the Chicago Daily Tribune’s infamous “Dewey Defeats Truman” headline has the political press been so badly blindsided by an election result.

To be fair, almost no one — including Brat himself — thought he could win. An underfunded candidate with almost no name recognition, Brat was essentially ignored even by the tea party groups he championed. His opponent was a seven-term incumbent with a national reputation and a brimming war chest. On Tuesday, he called his victory over Cantor a “miracle from God.”

“Anyone who tells you they saw this coming is just blowing smoke,” said L. Brent Bozell, the conservative activist and columnist whose group, For­America, supported Brat via social media but didn’t contribute money. “And, no, we didn’t, either.”

Brat’s most consistent coverage came from conservative media outlets that were attracted by his stance against loosening immigration laws. Breitbart.com, the news and commentary site founded by the late Andrew Breitbart, was an early supporter, and published a steady string of stories since February. On Wednesday, the site took a victory lap, leading with a headline reading, “Mainstream Media on Cantor Shocker: We Should’ve Read Breitbart News.”

Brat also attracted attention from other conservative sites, such as the Daily Caller and Townhall.com. And three prominent conservative media personalities — talk-show hosts Laura Ingraham and Mark Levin, and columnist Ann Coulter — repeatedly endorsed him on radio and TV, giving him legitimacy as a contender (Ingraham attended a rally for him last week).

But if voters in Cantor’s district were paying attention to these alternative voices, Beltway reporters largely weren’t.

Among the few mainstream reporters who wrote stories during the campaign about Cantor’s clashes with the tea party were Politico’s Jake Sherman and The Washington Post’s Jenna Portnoy and Robert Costa. Portnoy is one of two Post reporters based in Richmond.

In a Page One story in mid-May, Portnoy and Costa wrote that Brat “is gaining national attention as a potential threat to Cantor’s hold on his solidly Republican, suburban Richmond district.” It noted that these developments were “all the more remarkable because it is happening to a man widely seen as the likely next speaker of the House.”

“We, like everyone else, were surprised that Eric Cantor lost last night, but we didn’t miss the signs of trouble in his district and his problems with the tea party,” said Steve Ginsberg, The Post’s senior politics editor.

Sherman, a congressional reporter, wrote a story in late April that covered some of the dynamics of the race and included an interview with Brat. He was one of the few national reporters in Richmond on Tuesday to cover the Brat-Cantor campaign.

Sherman “was emphatic in his conversations with editors here that there were some very interesting currents at play in that race, and he pushed to write stories over the spring that I think do look very insightful in retrospect,” said John Harris, Politico’s editor. “He didn’t write predictive stories saying Cantor was going to lose, but he made it clear that Cantor was facing some genuine and potentially urgent political challenges.”

Other reporters may have been put off by the towering odds of Brat beating Cantor. What’s more, unlike state and national elections, reporters had scant public-opinion polling to signal the electorate’s mood or drive their coverage. There were only two polls taken on the race — one by Cantor’s campaign, the other by a new firm called Vox Populi — and both showed Cantor comfortably in the lead.

In the absence of such data, there may have been only one alternative: Talking to actual voters, an old-fashioned technique known as shoe-leather reporting.

The lesson for the media “is to be aware of short cuts,” said David Wasserman, House editor for the non-partisan Cook Political Report. “We can always look at money raised, ad dollars spent and polling and none of those would have pointed to trouble for Cantor. The reporters who took the pulse and sentiment of voters were on track. The rest of us should have delved deeper.”

Indeed, said Josh Kraushaar, political editor of the National Journal, “It’s a reminder to always be skeptical of what elected officials say, despite their positions of authority. Cantor’s campaign staff was downplaying the significance of very real voter dissatisfaction in his district, and probably had some success in muting coverage of his troubles. . . . Listening to voters is often as important as talking to the candidates and strategists behind the campaigns.”

Said Politico’s Harris, “As for me, I’ll confess to being stunned by the results.” But he adds, “I don’t think that’s anything to feel too sheepish about — one reason politics is fun to cover and follow is because it is full of surprises.”