Can Donald Trump govern this country?
He starts with several large advantages: the fervent support of white, working-class voters and the Republican control of Congress. In his victory speech, he struck generous themes of unity, vowing "to every citizen of our land that I will be president for all of Americans."
But Trump is going to learn very quickly that being president is far tougher than running for president. Even with his allies controlling Capitol Hill, he's going to face enormous obstacles that will make his job extremely difficult from Day 1.
Start with the way the campaign played out. Trump complained repeatedly that the system was "rigged" against him, but now it's the Democrats who will make that argument. The totally unprecedented -- and unjustified -- decision by FBI Director James Comey to interject himself into the campaign less than two weeks before Election Day stopped Clinton's momentum cold, and handed Trump a powerful argument to exploit his opponent's biggest vulnerability: her reputation for dishonesty. The impact is clear: Voters who decided at the last minute favored Trump by 5 points.
Add to Democratic grievances the facts that Clinton actually won the popular vote and lost key states by slim margins. Disappointment and frustration will be felt most keenly by women who hoped to see the first female president, and now believe that once again, a better-qualified woman has been passed over for a less-experienced man.
All these resentments feed into a second problem for Trump: an American system that was deliberately designed to check the power of even the most popular president. The new chief executive will soon learn a truism of Washington life: It's much easier to stop something than pass something.
Democrats are fully prepared to be hypocritical here. The same lawmakers who denounced the filibuster when Republicans used it against President Obama will now embrace the tactic with the fervor of a convert.
Their first focus will be the Supreme Court vacancy. And they will surely invoke Republicans who talked openly -- when they thought Clinton would win -- about blocking her appointees for her entire first term.
"The most difficult aspect of American politics these days is that governing moments are few and far between," wrote Princeton professor Julian Zelizer for CNN, before the election. "The forces of gridlock are extraordinarily strong."
Perhaps Trump's lack of experience will be an asset; perhaps he'll be able to combat these "forces of gridlock" with a fresh eye. But governing is a profession, and an honorable one. Trump would never turn his business over to amateurs. They'd make too many mistakes. An amateur in the White House is a far riskier bet.
Trump's problems don't end with Democrats. His own party is badly fractured, with a core of hard-line conservatives determined to push him toward a purist ideology and away from being a president "for all Americans."
Congressional leaders like House Speaker Paul Ryan openly disdained Trump, and have a lot of fence-mending to do. Some party activists will agree with GOP strategist Peter Wehner who wrote in The New York Times that "a party that is recast into the image of Mr. Trump is something many of us would want nothing to do with."
Another problem for Trump: He made a series of promises he cannot possibly keep. Some, like repealing Obamacare, will almost certainly be blocked by Senate Democrats.
Others simply cannot work, even if Republicans held every seat in the Senate. Trump won the votes of many dispirited workers by vowing to restore the manufacturing jobs that have fled the industrial heartland. He blamed closed factories on bad trade deals and argued that a stronger negotiator could reverse the trend.
But every economist knows that's a lie. Manufacturing jobs were mainly lost because of two unstoppable forces: technological innovation and globalization. Global markets require companies to stay competitive by making products in low-wage countries. Those jobs won't come back.
Another promise that Trump can never keep: deporting the 11 million undocumented workers who fill vital roles in the economy, and often have children who are American citizens.
Trump cannot control markets, which plunged worldwide as his victory loomed. And neither China nor ISIS will be impressed with his bluster. How long will it take for disillusionment to set in?
President Obama graciously told Americans that "our democracy has always been rowdy and raucous. We've been through tough and divisive elections before and we've always come out stronger for it."
But his optimism will be severely tested by a Trump presidency.