Carlo Allegri / Reuters

Everyone already knows the struggle for control of the White House will be the biggest domestic story of 2016. The campaign has already generated record television ratings and volcanic eruptions of vitriol. By November, it is likely to become the most expensive political race ever. Already, it is unlike any campaign Americans have seen before.

But, as the song says, some fundamental things apply.

Presidential elections are shaped by the collision of long-term national trends and short-term political tactics. This year will be no exception. Some of the key questions that will determine which party takes the presidency will be settled within the political system itself; others will turn on events beyond the campaign. For me, six questions, drawn from both categories, seem most likely to decide the outcome.

1. Who wins the battle for control of the Republican Party?

Once again, the GOP is dividing between white-collar, center-right “managerial” voters and “populist” voters drawn from the overlapping circles of working-class whites and evangelical Christians. When those two blocs have diverged before, the managers’ preference (think John McCain in 2008 and Mitt Romney in 2012) has usually prevailed. But this year, no candidate has consolidated the managerial wing, and the race’s two front-runners are antiestablishment populists relying mostly on blue-collar (Donald Trump) or evangelical (Ted Cruz) voters. Many party strategists fear that neither candidate could win the general election. The primaries will determine if the GOP’s managerial mainstream can unite to seize the nomination, or if the party will leap into the unknown with Trump or Cruz.

2. Can Democrats reassemble the “coalition of the ascendant?”

That’s the term I coined in 2008 for the groups that underpin the modern Democratic electoral coalition: millennials, people of color, and college-educated, single, and secular whites, especially women. Those groups are growing in the electorate, and if Democrats can turn them out and maintain their recent advantages among them, Republicans could win the presidency only by amassing dauntingly high margins among all other whites. But it remains to be proven whether Democrats can energize those groups as effectively as they did with President Obama on the ballot. Polarizing proposals from the GOP front-runners could help motivate them, but front-runner Hillary Clinton draws surprisingly tepid ratings from some of these constituencies. One related wild card is the continued tension between African-Americans and mostly Democratic big-city mayors over policing practices. This could depress black turnout from its record high when Obama ran.

3. Is ISIS advancing or retreating?

Apart from the structural hurdle of winning three consecutive presidential elections (since World War II, only Republicans managed the feat, from 1980 through 1988), the biggest challenge facing Democrats in 2016 may be the public verdict that Obama’s approach to fighting terror, and stabilizing the Middle East more broadly, has failed. The complicating factor is that most Americans also believe the Republican approach (as defined by George W. Bush) failed; we have employed both the velvet glove and the iron fist and lost faith in both. As the nominee, Clinton might successfully separate herself from Obama on these issues. But any Democratic candidate may benefit greatly if ISIS loses ground—and will suffer if it grows more threatening.

4. Does job growth produce wage growth?

If job growth continues its recent trajectory (over 215,000 a month since January 2013), the economy would create fully 10 times as many jobs in Obama’s two terms (around 12 million) as during Bush’s (1.2 million). But Obama has received little political credit for those gains because wages and incomes have lagged: Median income is lower today than in 2000. Faster wage growth would reshape the economic debate in 2016.

5. What is Obama’s approval rating on Election Day?

The answer to this question may turn on the two immediately above. But no single number may matter more than Obama’s standing with voters. Exit polls found that roughly four-fifths of voters who approved of Ronald Reagan in 1988, Bill Clinton in 2000, and Bush in 2008 voted for their party’s nominee to succeed them. Exactly 88 percent of the voters who disapproved of Reagan and Clinton voted for the other party’s candidate; for Bush the number was two-thirds.

6. Who will win Virginia?

The Old Dominion may now be the state most likely to vote with the presidential winner. The Democrats' control of the "blue wall"—the 18 states that have voted Democratic in every presidential election since at least 1992—means they can plausibly reach 270 Electoral College votes without capturing either Florida or Ohio, the states usually considered decisive. If the Democrats defend the blue wall, add New Mexico and Nevada (which lean strongly toward them), and hold Virginia, they will win the White House if they can capture any single additional swing state like Iowa, New Hampshire, or Colorado (not to mention Florida or Ohio). For that reason, expect much discussion of Virginia’s two Democratic senators (Tim Kaine and Mark Warner) as possible vice presidential nominees—unless Marco Rubio or Cruz win the GOP nomination. That would heighten Democratic interest in Housing and Urban Development Secretary Julian Castro, Democrats' most credible Latino option.

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