ONE HUNDRED days into the Donald Trump presidency, we have neither achieved the nirvana he promised nor entered the dystopia critics, including us, feared. Since nirvana was never likely, it may be more productive to examine why we have, so far, avoided the worst. Preliminary thanks are owed to Congress, judges, the Congressional Budget Office, the American citizenry, and voters in the Netherlands and France.

And, to a highly limited extent, to the president. He did not, on Day One, tear up the North American Free Trade Agreement, the Iran nuclear treaty or the Paris climate change accord. He has not abandoned NATO or embraced Russian President Vladi­mir Putin. He has appointed sober-minded advisers to important positions, notably defense secretary and (on his second try) national security adviser. When Syrian dictator Bashar al-Assad used chemical weapons against defenseless civilians, Mr. Trump responded with appropriate force.

On the other hand, Mr. Trump’s early record also offers cause for alarm. His inexperience and ideological drift have been evident in his administration’s slow and lurching start. Though a consistent foreign policy has yet to emerge, there is reason to fear that he will diminish U.S. economic, political and moral leadership in the world: his early withdrawal from a pan-Pacific trade agreement, for example, and the chilling moral equivalence in his response to Bill O’Reilly’s question about Russia’s killing of dissidents and journalists. “There are a lot of killers,” Mr. Trump replied. “You think our country’s so innocent?” His bombing of Syria has not been followed by any dis­cern­ible strategy to address that nation’s horrific civil war.

Mr. Trump has reversed a generation-old trend toward openness, becoming the first president in modern times to conceal his tax returns and scrapping an Obama-era policy of publishing a list of White House visitors. He and his spokesmen frequently ignore facts and embrace misinformation. If he gets his way on policy, the nation will plunge more deeply into debt, global warming will accelerate and millions of vulnerable Americans will lose access to health care while the wealthy are further enriched.

But some of these policies are meeting resistance. When the nonpartisan CBO estimated that 24 million Americans would lose health coverage under Mr. Trump’s plan, even Republicans in Congress balked. Opposition bloomed at town hall meetings across the country. There have been women’s marches and scientists’ marches — and some politicians have listened. Federal judges have slowed Mr. Trump’s efforts to go after immigrants and immigration, efforts that at least in their early versions were closer to demonization than serious policy. Meanwhile, voters in Europe, perhaps sobered by what they see in the United States, have been choosing centrist internationalism and rejecting the kind of ethno-nationalist politics that animated the most dangerous of Mr. Trump’s supporters.

President Trump. (Jim Lo Scalzo/Associated Press)

No conclusions can be drawn from any of this. Will Mr. Trump allow his team to shape a more traditional foreign policy, with a dose of trade belligerence, or will he undermine long-standing alliances — or will he jump from one stance to another day by day? We don’t know. How will the White House respond when tested by a crisis, as it surely will be? Will Congress and the FBI seriously investigate Mr. Trump’s connections to Russia and that nation’s interference in the 2016 election?

Until that last question is answered, it is surely too soon to say the system has worked. But the system is at work, and — designed by the Founding Fathers, shaped and tested over time, pushed and pulled by millions of engaged Americans — it remains an impressive piece of machinery.