We really don't know what Donald Trump is going to do when he becomes president on Jan. 20, 2017.

Sure, there are signs of a general ideological direction — the large number of right-wing staffers and Cabinet nominations, the reckless tweets about China and flag burning — but in many cases, they have been countered by contrary signs, including winks and nudges to The New York Times and other media outlets about possible areas in which moderation could prevail.

The ultimate source of our uncertainty is Trump's lack of consistent attachment to the ideological program and institutional establishment of the post-Reagan Republican Party (including its intellectual infrastructure: the array of magazines and think tanks in which policy is regularly debated). More than any president in recent memory, Trump is a free agent in both foreign and domestic policy.

One of the biggest mysteries concerns whether Trump will resolve or intensify a contradiction that runs right through the modern Republican Party. That's the clash between the rhetoric of presidential aspirants and the reality of how they govern in office. When campaigning, Republicans talk like populists, about jobs, growth, and the good old-fashioned common sense of the American people. But once they reach office, they invariably end up serving the interests of the party's fabulously wealthy donor class by striving to cut upper-level income taxes and regulatory burdens on businesses.

To resolve this tension, thoughtful Republicans typically follow such writers as Adam Smith, Friedrich Hayek, Ayn Rand, and Milton Friedman in suggesting that what benefits entrepreneurs benefits everyone. When the rich pay less in taxes and business owners get to pursue profits in a favorable regulatory environment, overall economic growth increases, which (in theory) leads to job creation and higher wages. As the saying has it, a rising tide lifts all boats — not just the luxury vessels docked at the yacht club.

Trump's entire campaign seemed designed to call this bluff. He portrayed himself as the great populist, a champion of the working class — people who've been left behind by economic policies that have been pursued by both parties in recent decades. During the campaign, this translated into Trump portraying himself as a fierce opponent of immigration and free trade, and a valiant defender of steep tariffs, entitlements, and major spending on infrastructure (which would presumably put under-employed working-class voters back to work).

Since winning the election, Trump has demonstrated his commitment to this stance by strong-arming companies to keep jobs in the country, threatening to impose punitive tariffs of 35 percent on goods shipped back to the country when a company moves jobs overseas, and picking a Twitter fight with China about its practice of currency devaluation.

All of this would seem to indicate that Trump is trying to resolve the GOP's tension between populism and plutocracy in favor of the former. As one of his economic advisers recently put it, Trump is actively transforming the GOP into a "working-class party."

But is this true? Or will he merely end up increasing the tension even further, driving the party into outright incoherence?

From the beginning, the latter has been a distinct possibility — and it's only become more likely during the transition.

Consider all the billionaires and titans of finance Trump is lining up to staff his administration. And the fact that, like every Republican presidential candidate since Reagan, he favors a massive tax cut for upper-income earners, despite the lack of popular support for such a policy among the American people in general and even Republicans in particular. And the fact that Republican options for replacing the Affordable Care Act would abandon the goals of universal and comprehensive health insurance coverage, leaving many working-class voters with less support than they now enjoy.

And then there's the considerable uncertainty about whether Republicans in the House and Senate will go along with Trump's more explicitly populist plans — the border wall and deportations, the tariffs (and possible trade wars), the ambitious infrastructure spending. The GOP is deeply divided, with some supporting Trump's blue-collar agenda and many others, ranging from Sarah Palin (who denounced as "crony capitalism" Trump's effort to get Carrier to keep several hundred jobs in the U.S.) to The Wall Street Journal's influential editorial page, extremely skeptical and even overtly hostile to it.

If Trump's populist agenda comes to little or nothing — if it becomes just the latest (and most egregious) example of a rhetoric of populism being used to sweeten a policy agenda that overwhelmingly benefits the rich — the GOP is going to have a major problem on its hands.

The problem will be familiar — the same one that spawned and propelled Trump's candidacy — but the next time it will be even larger and more intense. Trump's disruptive campaign succeeded because it validated and channeled popular disgust and disappointment at the establishments of both parties. What do you think its successor will look and sound like when it directs its furies against those establishments once again, though this time adding the Trump administration to the indictment?

That's what Republicans, and all Americans, are facing as the Trump era dawns: the prospect of Trump turning the GOP, for the first time, in a genuinely populist direction — or else setting the party up for further disruption or defeat at the hands of a left-wing populist.

Which way will Trump and the party go? Just over six weeks out from Inauguration Day, the answer remains a mystery.