“Game Change 2” has just been published, and horse-race junkies currently feeling the aches and fevers of election withdrawal (Virginia and New Jersey’s gubernatorial races -- much less New York’s puny mayoral race -- hardly provided a fix) are rejoicing. As well they should. “Game Change 2” -- the actual title is “Double Down: Game Change 2012” -- is a joyous romp through the seedy underbelly of presidential campaigning. It’s a cure for the off-year shakes.

It’s also a marvel of reporting. Any time three staff members met in a room to badmouth a colleague or a candidate admitted to a moment of stress or self-doubt, authors John Heilemann and Mark Halperin appear to have been sitting in the corner, scribbling notes.

As the subtitle indicates, the book is ultimately an account of the actors and moments that changed the game (“game,” of course, being the presidential election). From the dead end New Jersey Governor Chris Christie hit in the vice presidential vetting process to President Barack Obama’s crisis of confidence before his second debate against Mitt Romney, the course of the election -- thus the country -- seems to reset every few pages. The hinge of history is well-oiled, it seems.

But when you buy “Game Change 2,” you should also buy its opposite -- “The Gamble,” by political scientists John Sides and Lynn Vavreck. It, too, is an account of the 2012 election. But it signals its contrasting point of view in its first sentence: “68,” the authors wrote. “That is how many moments were described as ‘game-changers’ in the 2012 presidential election.” The rest of the book is dedicated to proving that almost none truly were.

Plot Points

Modern campaign journalism was born the day Theodore White published “The Making of the President 1960.” White was the first to frame a campaign as a novel, portraying the candidates as protagonists, campaign staff as supporting characters, and various campaign decisions and events as crucial plot points.

White came to lament the example he had set. “By the 1972 Nixon-McGovern campaign, White acknowledged that his preoccupation with character and strategy had given birth to quadrennial media frenzies in which presidential politics became a game,” wrote Joyce Hoffmann, author of “Theodore H. White and Journalism as Illusion.” Hoffman said White “rued the atmosphere of endless critical media attention in which candidates were forced to function, and he took part of the blame.” (“If you write about this, say that I sincerely regret it,” White told Timothy Crouse, author of “The Boys on the Bus,” during the 1972 election.)

Sides and Vavreck’s book is an overdue corrective. They weren’t embedded in a campaign or buddies with top strategists. They don’t usher you inside the room. But they have something that campaign reporters lack: data. Lots and lots and lots of it.

Sides and Vavreck partnered with the online polling firm YouGov and repeatedly surveyed an enormous pool -- 45,000 Americans. They analyzed news coverage from 11,000 media outlets -- which is about 10,863 more outlets than I can recall covering the election. They have data on who bought how many television spots and where. Underpinning their real-time information are decades of supporting political-science data and theory.

The result is that while most election narratives track the inputs of the campaign, Sides and Vavreck track the outputs. They know less than traditional political reporters about what the campaigns wanted to do but much more about what actually got done.

More Fierce

Sides and Vavreck’s data led to what might be called the Slim Charles theory of presidential elections, so named for the character on HBO’s “The Wire,” who said, “Game’s the same. Just got more fierce.”

Most “game-changers” actually prove to be, in Sides and Vavreck’s term, “game-samers.” When Obama, addressing public infrastructure’s role in supporting business, said, “You didn’t build that,” the Romney campaign and news media went wild. The polls didn’t budge.

Remember the attack ads portraying Romney as a ruthless boss at Bain Capital LLC, firing blue-collar workers to increase profits? The numbers for the poll question measuring whether voters thought Romney “cares about people like me” stayed flat. Even Romney’s notorious “47 percent” video failed to have lasting impact on the race.

Campaigns are less successful at persuading undecided voters than they are at encouraging their own partisans to grow more fierce. The manic charges and countercharges of an election mostly remind voters which side they were on to begin with. “Strengthening people’s natural partisan predispositions is one of the most consistent effects of presidential campaigns,” Sides and Vavreck wrote. “Democrats or Republicans who at the start of the campaign feel a bit uncertain or unenthusiastic about their party’s nominee will end up dedicated supporters.”

This is, they noted, an established finding among political scientists. As a 1940 study of voters concluded, “Knowing a few of their personal characteristics, we can tell with fair certainty how they will finally vote: They join the fold to which they belong. What the campaign does is to activate their political predispositions.”

The 2012 numbers bear that out: Eighty-nine percent of Democrats voted for Obama, while 88 percent of Republicans went for Romney -- a more neatly partisan breakdown than polls of either Democrats or Republicans suggested in 2011. The main effect of the election was to persuade partisans to come home.

That’s not to say that presidential campaigns don’t matter. The catch is that the opposing campaigns matter simultaneously. By the time of the general election, they have both grown pretty good at what they do. “Unlike candidates in many down-ballot races, the major-party presidential nominees are usually evenly matched,” Sides and Vavreck wrote. “They tend to have roughly equivalent resources: lots of money, professional campaign organizations, and so on. In short, they are good at competing, most of the time, and this means their efforts neutralize each other.”

Key Actors

Inside the campaigns, thousands of people are working, plotting, scheming, worrying and having all those caffeinated strategy meetings that “Game Change 2012” chronicles so enjoyably. It really is a tense, consequential effort. But the results are broadly predictable: The two sides will make mostly sound decisions interrupted by occasional mistakes (“gaffes”), and the election outcome will mostly be driven by partisan allegiances and voter assessments of the economy and the incumbent president.

Indeed, a data model the authors built in June 2012 -- before the summer ad blitz, Romney’s pick of Paul Ryan for vice president, conventions, debates and all the rest -- predicted Obama would win 52.7 percent of the two-party vote. Sides and Vavreck were off: He won 52 percent.

For anyone who covers campaigns, “The Gamble” is a discomfiting read. First, it suggests that much of what we cover simply doesn’t matter. Second, it rests on a premise we don’t always want to admit: that the political news media are key actors in the drama.

If most election narratives cast the campaign staff as key actors, “The Gamble” focuses on the centrality of the news media. Over and again, Sides and Vavreck record the candidates acting -- and the media reacting, filtering, covering, assessing. That process determines what information voters do and don’t hear. It’s also a process that members of the news media tend to overlook, in part because it raises complex questions about their role in shaping what they cover.

The book lays bare news media bias. It’s not in favor of Republicans or Democrats, however, but of volatility and sensationalism. The news media overestimate the effects of micro events (those 68 “game-changers") and underestimate the relatively stable foundation -- partisanship, the state of the economy -- on which those events play out. The day before the 2012 election, Wall Street Journal columnist Peggy Noonan wrote: ‘‘We begin with the three words everyone writing about the election must say: Nobody knows anything. Everyone is guessing.’’ By that point, reams of data had been collected, and they were clearly pointing to an Obama victory. Noonan and others were simply stumping for the news media’s perennial favorite candidate: excitement.

There’s no better book than ‘‘Double Down” for reliving that excitement. But there’s no better book for understanding it -- and the political structures that will continue shaping U.S. elections in 2016 and beyond -- than “The Gamble.” For campaign journalism, the book is a game-changer.

(Ezra Klein is a Bloomberg View columnist.)

To contact the writer on this article: Ezra Klein in Washington at wonkbook@gmail.com.

To contact the editor responsible for this article: Francis Wilkinson at fwilkinson1@bloomberg.net.