AFTER NEARLY two years of waiting, Americans have some preliminary answers about Russia’s interference in the 2016 election. Attorney General William P. Barr on Sunday revealed that special counsel Robert S. Mueller III found no collusion between Donald Trump or his 2016 campaign with the Russian effort. But Mr. Mueller did not answer with the same clarity whether President Trump unduly interfered with law enforcement. That will be a matter for Congress and the public to consider as Mr. Barr releases more information — as he must.

Where there is smoke, there is not always fire. Despite questionable meetings between Trump officials and Russians, Mr. Mueller found that the investigation “did not establish that members of the Trump Campaign conspired or coordinated with the Russian government in its election interference activities.” To take one key example, the June 2016 meeting between Mr. Trump’s senior campaign staff and a Russian lawyer was deeply unwise. The campaign should have reported to the FBI the Russian lawyer’s interest in meeting, rather than bringing her into the campaign’s inner sanctum. But, based on Mr. Barr’s Sunday summary, this did not reflect a broader coordination between the Trump campaign and Moscow.

That much should be a relief to Americans worried that the nation’s senior leaders acted as agents of a foreign power during the 2016 election. On the other hand, Mr. Trump’s bizarre refusal to acknowledge the Russian interference, and his unceasing assaults on Mr. Mueller’s investigation, are all the more confounding. It is still not out of the question that Mr. Trump’s disturbing deference to Russian President Vladi­mir Putin is repayment for the Kremlin’s help during the presidential race. But it seems more likely that Mr. Trump is simply a Russian apologist. That is not comforting.

Mr. Mueller also examined whether Mr. Trump obstructed justice as he bullied the Justice Department. Here, Mr. Mueller’s call is trickier — and will require a lot more information for Congress and the public to make their own judgments. Mr. Mueller “did not draw a conclusion — one way or the other — as to whether the examined conduct constituted obstruction,” Mr. Barr revealed. Mr. Mueller made clear this was not an exoneration. Mr. Barr subsequently determined that there was not enough evidence to warrant an obstruction-of-justice charge against the president.

Given the apparent closeness of the call — and Congress’s role in overseeing presidential behavior — it is crucial that Mr. Barr’s vague description of the obstruction question not be the last word on the matter. To the greatest extent possible, the public must see the record that Mr. Mueller collected.

There is a lesson for Mr. Trump and his partisans, too: The Mueller probe was no witch hunt. There are public servants who put the interests of truth and duty above tribal loyalty, and many of them work at the Justice Department. The president was wrong to trash and undermine this institution for the past two years — and to continue trashing it Sunday, after Mr. Barr had made his report.

Mr. Barr deserves credit for releasing information as quickly as possible. He has, so far, kept his promise to maximize transparency in sharing material from the Mueller probe. In his Sunday release, the attorney general warned that there would be material he could not publicize. We nevertheless expect that Mr. Barr will lean heavily toward transparency. The alternative would be that questions remained unanswered — and suspicions festered — around the president’s behavior.

Read more:

E.J. Dionne Jr: Six takeaways from Barr’s letter about Mueller’s probe

Jennifer Rubin: What Barr’s letter about the Mueller report says and doesn’t say

Randall D. Eliason: Mueller’s investigation is over. Americans should breathe a sigh of relief.

David Ignatius: The Mueller report won’t fix the problem underlying it all

Harry Litman: The Mueller report will be released, one way or the other