In the 2012 election, 5,667,658 small donors contributed to the Barack Obama and Mitt Romney campaigns, giving $370 million. But another $470 million came from just 100 people. That’s a phenomenal imbalance.

The campaign contributions didn’t stop there — not even close. A total of $7 billion was spent on all races in the 2012 election by the candidates, parties and outside groups, with outside groups outspending the Republicans and Democrats for the first time ever. Enabled by the Supreme Court decision in the Citizens United case, megadonors can now make political contributions in unlimited amounts, which they are doing with increasing secrecy.

Kenneth P. Vogel digs into the stories behind those numbers — the rivalries between Karl Rove and the Koch brothers, how Obama went from campaign finance reformer to big-money raiser — in his revealing new book, "Big Money: 2.5 Billion Dollars, One Suspicious Vehicle, and a Pimp — on the Trail of Hijacking American Politics" (PublicAffairs, 320 pp, $27.99).

In the course of his investigations Vogel, who writes about campaign funding for Politico, dogged the Koch brothers’ retreats for donors and politicians, got scolded by Rove, and was thrown out of funders’ meetings by threatening security agents. He spoke to us by phone from Politico’s offices in Arlington, Va.

Q. These donors gave $7 billion, and nothing much changed. President Obama was re-elected, the balance of power in the Senate and the House remained the same. Do you think they’ll be discouraged by the low return on investment?

A. I think a lot of folks treat this almost like a hobby. Like Steve Ballmer from Microsoft who just bought the L.A. Clippers — if you have enough money to pay $2 billion for a sports team, you’re probably doing pretty well and not super concerned about making money off the team. You think ‘Hey, I made all this money at Microsoft. I bet that my instincts and business savvy will apply to running a team.’ If you’re a sports junkie, wouldn’t it be cool to tell the GM to draft this player, or the coach to run more plays for that player? It’s similar with the megadonors.

These folks (megadonors) have all this money, and they’re doing something they believe in. If they win, great; if they don’t win, they had fun doing it. Foster Friess got to ride around in Rick Santorum’s truck during the Iowa caucuses, going to all 99 counties, doing town halls at pizza places. He loved it. It’s like political fantasy camp. For him, to spend $2 million on a ‘super PAC’ that supported Rick Santorum, that helped Santorum win the Iowa caucuses — a shocking result that not many people predicted — to have the front-row seat for that is probably more than worth it.

Q. With billions of dollars to spend on television ads, will candidates even bother to do the kind of campaigning Santorum and Friess did, visiting pizza parlors across Iowa?

A. I think you need the big money to get in the game, but once you’re in the game you still need to do the retail politics. And you still need to have a compelling message. Mitt Romney had all the money and he was so good at (cultivating donors), but so deficient in delivering the message and connecting with people. There’s only so far the money will take you …

Q. How do you make campaign finance interesting for general readers?

A. It’s certainly a wonky subject, one that is easy to ignore. It’s these gigantic numbers, nasty ads, and conniving robber-baron donor archetypes. But the goal was to present a much more nuanced reality, and to show the motivations of all the players involved.

On the Democratic side there are two rising young donors playing an increasing role in Democratic politics — the Mostyns, Steve and Amber. They’re self-made Houston trial lawyers; if they’re not billionaires, they’re getting pretty close. They’re young, in their 40s, and they like to hang out and drink and party, something different than your idea of the traditional megadonor.

Q. On the conservative side, in addition to Friess, there are the Koch brothers — who come across in your book as having distinct personalities.

A. There are actually four Koch brothers, and all of them have very distinct personalities. We think of them as just Charles and David ... because they’re the most politically active and give the most money to politics. Even there, there’s definite variance between the two. Charles Koch is more of the Libertarian crusader. In some ways he’s motivating this increased spending (outside the system) that has benefited the Republican party, but he kind of has no patience for either party. Whereas David Koch seems to enjoy the social side of politics. He was a delegate to the Republican National Convention in Tampa and hosts fundraisers at his estate in the Hamptons.

While David is becoming increasingly Republican, he also has these Libertarian instincts. I had a chance to chat with him at the Republican National Convention, and ask him about some of these places where he seems to be outside the lines of the party, and he didn’t back away at all. He said, ‘I favor gay marriage.’ I said, ‘What about Mitt Romney, the candidate you’re here to support? He doesn’t favor gay marriage.’ He said, ‘I disagree with him!’ That was interesting and frank and candid … He would favor defense cuts. He would even potentially be open to tax cuts. It was interesting to watch the people around him as he’s sharing his heartfelt views: They’re kind of cringing, because they’re Republicans and would prefer he hew to the party line.

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Q. How did you wind up making campaign finance your beat?

A. My first job in journalism was covering general assignment for the Journal Inquirer in Manchester, Conn., and one of the coolest assignments I had was covering the Hartford County Sheriff’s Office. It was a scandal-plagued office that had a number of campaign finance investigations — the campaigns for Hartford County sheriff were notoriously controversial in the way that money was raised and spent. Any political story that you cover, there’s always a money angle. I naturally gravitated toward it to the point that it became my beat.

Q. More than once you stationed yourself in hotel lobbies and other semi-public parts of private funder meetings to watch and listen. But if they found you out, you were shown the door. Won’t people recognize you after this book?

A. I think I was already toward the end of the window; people already recognized me. A combination of having done a lot of this stuff before, as well as doing TV and being generally recognizable — although more recognizable to people who take an active and acute interest in this … I don’t want to say the jig is up, because I’m hoping there will still be ways to cover this type of stuff and get inside, but it’s becoming increasingly harder.

Q. In the book you describe a weekend in Indian Wells, Calif., at a hotel where the Koch brothers’ retreat overlapped with the Stagecoach Country Music Festival.

A. It was the epitome of country cool. The cowboy hats, the bikinis, the light beers, throwing the football around in the pool. The septuagenarian and octogenarian all-white male industrialist, sportcoat-clad (Koch) crowd looked askance at this spectacle. There was no confusion as to who was with which crew. It was the first and only time I’ve ever gotten into one of those conferences. They couldn’t rent out the whole hotel because of Stagecoach.