ONE of the puzzles of the 2016 campaign, unexpectedly defined by the ascent of a billionaire reality TV star and a septuagenarian Vermont socialist, is why now? Yes, voters are angry, yes, they’re exhausted and disgusted and cynical about everything. But why is everything boiling over in this particular cycle, in this presidential campaign?

Consider: The economic picture is better than it was in 2012, when Republican primary voters settled for Mitt Romney and an incumbent president was re-elected pretty easily. (In both Iowa and New Hampshire, the unemployment rate is currently under 4 percent.) The foreign policy picture is grim in certain ways, but America isn’t trapped in a casualty-heavy quagmire the way we were in 2004, when Democratic voters played it safe with John Kerry and George W. Bush won re-election.

As Michael Grunwald argued recently in Politico, the worst-case scenarios of the post-Great Recession era haven’t materialized. Obamacare is limping along without an imminent death spiral, and health care costs aren’t rising as fast as feared. The deficit has fallen a bit, and inflation is extraordinarily low. The stock market is wobbly, but we haven’t had a double-dip recession.

On the cultural front, out-of-wedlock births are no longer rising. Abortion rates have fallen. Illegal immigration rates are down.