The first 100 days of Donald Trump's presidency have been chaotic and unpredictable. Reporters who covered it recount the events that dominated the news. (Alice Li,Jayne Orenstein,Julio Negron/The Washington Post)

Donald Trump’s first 100 days in office have involved an awful lot of foreign policy. We’ve seen the withdrawal from the Trans-Pacific Partnership (TPP), the strike against Syria, the ongoing tensions with North Korea and several high-profile meetings with major world leaders.

As many commentators — and recently, President Trump himself — have pointed out, the 100 day mark is somewhat artificial. But no matter how much or how little time goes by, assessing foreign policy is hard — because so much of it is invisible.

We see only the outward product, so it’s hard to know how much of the stated policy is what’s really being pursued behind the scenes. The signs, however, suggest that Trump has a “Potemkin” foreign policy: What we see is mainly for show; behind it, there’s not really much going on.

How much has Trump’s foreign policy shifted from Obama’s?

Most new presidents try to differentiate themselves from their predecessors on foreign policy. Trump has been no exception. Trump did make some clear breaks with Obama, most notably by walking away from the TPP. But others have noted recently that in other respects, Trump seems to have backed off his campaign rhetoric in favor of more conventional even Obama-like policies in the Middle East and Japan.

So which it is? Break with the past, or a return to the mainstream?

We just don’t know. As Tom Pepinsky has written, when we try to assess things like how powerful a leader is or how much a policy has changed, it’s difficult — because what we see could be explained by either of two competing explanations. So, as he notes, weak leaders often try to talk loudly about how strong they are, while strong leaders are much quieter about wielding their power. “Weak leaders often act like strong leaders, and strong leaders often act like they are indifferent.”

Assessing Trump’s foreign policy leads to another version of this problem. It is true that at least outwardly, Trump has backed off some of his most dramatic rhetoric on foreign policy, as when he stated that he no longer believes NATO is “obsolete.”

But the “mainstreaming” of Trump’s foreign policy may be an illusion — and not just because he might change his mind again. Rather, the conventional policies to which he appears to be reverting no longer rest on the firm foundation they once did, in large part because Trump is actively or passively allowing the foundation of those policies to erode.

It’s what we can’t see that matters

As James Goldgeier and I wrote not long after the inauguration, a lot of good foreign policy is invisible. Things like alliances, diplomacy (the boring, day-to-day kind, not the splashy deal-making kind), and even free trade agreements bring benefits that are hard to see but pay off in the long run.

Unfortunately, a lot of bad foreign policy is invisible, too. In particular, inaction can leave a country unprepared and isolated when a crisis hits. Trump’s failure to appoint staff — which he says is partly a deliberate policy — can “hollow out” foreign policy, as William Burns has put it. Consider the Trump budget proposal, which includes dramatic funding cuts to the State Department andforeign aid. Such cuts would take away important diplomatic levers for handling crises. Even if these cuts are not as draconian in the end, the proposal signals that the White House doesn’t value non-military policy tools and probably won’t rely on them much.

All this is like deferred maintenance: If you don’t fix up your house, when a big storm blows in, the roof is more likely to leak. There are still excellent people in the government’s foreign policy community, including some of Trump’s own appointments. But the appearance of competence or continuity here and there may be masking a lot of rot or termite damage.

President Trump meets with Saudi Defense Minister and Deputy Crown Prince Mohammed bin Salman bin Abdulaziz Al Saud in the Oval Office on March 14, 2017. Vice President Mike Pence, center right, and White House senior adviser Jared Kushner, right, listen. (Jabin Botsford/The Washington Post)

Changed policies, or mere rhetoric?

For the same reason, it’s hard to tell whether Trump’s public foreign policy statements will guide his actions. How can we assess what it means when he makes a statement that appears more mainstream than what he’s said in the past? Consider his new position that NATO is not obsolete. He might be recognizing the value of NATO; he might be accepting the reality that it’s harder to disengage from alliances than he thought; or he might simply be trying to please the person he’s meeting with (in this case, NATO Secretary General Jens Stoltenberg).

But if he really does believe alliances are bad for the United States — and as Thomas Wright noted long before the election, Trump has held that view for a long time — he could — simply through neglect — seriously harm alliance relationships. That bill would come due in a crisis.

A Potemkin foreign policy?

A lot of international politics is structural and hard for leaders to change. That’s one reason we are reading that Trump has few good options in North Korea, for example. But a president can navigate a set of bad choices in a sturdy, well-crewed ship or alone in a leaky rowboat. The problem is that we can’t see his boat. We just don’t know the answers to so many questions, like how much is Trump listening to his experienced National Security Adviser H.R. McMaster, or others steeped in particular foreign policy areas.

We do have some hints. Trump’s insistence on public credit where other presidents would recognize the need to lay low; his regular insistence on his own strength and “winning”: these strike observers (here and internationally) as bluster, not competence.

At the end of 100 days, then, Trump may have changed less than his campaign rhetoric led us to expect. But what appears to be a new policy position might collapse if we poke at it too hard. With his legislative agenda stalled, Trump may turn more to foreign policy, as presidents often do when they can’t get things done domestically. We may know sooner than we think whether Trump’s foreign policy has meat on its bones, or if it’s all for show.