President Trump rejoiced in the death of former Special Counsel Robert Mueller.It is sadly part of a pattern for Trump. The film director Rob Reiner and his wife, Michelle; former Representative John Dingell; former Secretary of State Colin Powell; former Senator John McCain—Trump had something wildly inappropriate to say after the passing of each of them, and others too.“Good, I’m glad he’s dead,” Trump wrote on Truth Social shortly after Mueller’s death was announced on Saturday. This comment was not just indecent. It was also ungrateful. Trump owes Mueller a huge debt of gratitude. Mueller’s straight-arrow approach to law enforcement rescued Trump from a danger of his own making.Trump hates Mueller for the investigation into possible Russian interference in the 2016 presidential election, which was certainly embarrassing for Trump. But Mueller interpreted his mandate in ways that protected the president, and he delivered the best possible conclusion for Trump, stating in his report: “The investigation did not establish that members of the Trump Campaign conspired or coordinated with the Russian government in its election interference activities.”Mueller confirmed that Russian spy agencies engaged in a “sweeping and systematic” campaign to help Trump at the expense of Hillary Clinton. He confirmed that Trump’s inner circle welcomed this help—most vividly in a June 9, 2016, meeting at Trump Tower, in which a Russian representative offered dirt on the Clinton campaign to Jared Kushner, Paul Manafort, and Donald Trump Jr. But although Mueller mapped the dots, he could not connect them.[Jonathan Lemire: Donald Trump is nothing like Robert Mueller]The questions Mueller was assigned to answer remained questions at the end: Why did Russia help Trump? What did Trump’s inner circle know about this help? How was this help connected to Trump’s pro-Russian attitudes as a candidate and a president? Mueller’s report insisted that the absence of answers did not amount to an exoneration of Trump. But without a clear indictment, Trump could effectively dismiss the whole matter as a “hoax.”Mueller enabled this distortion of the facts. He not only accepted the Department of Justice guidance that a serving president could not be indicted for a federal crime, but also inferred that this meant a president could not be tried. Because a president could not be tried, he could not be acquitted; because he could not be acquitted, it would be unfair for Mueller’s report to include any allegation that the president could not legally refute.Contrast Mueller’s approach with that of the next special counsel to investigate a president, Robert Hur. Hur was assigned to investigate allegations that President Biden had improperly removed documents to his private residence after leaving the vice presidency in 2017. In February 2024, Hur found no basis to proceed with a case. He added an explanation: If a case went to trial, a jury would likely find Biden to be a “sympathetic, well-meaning, elderly man with a poor memory.” Hur added that Biden appeared to suffer from “diminished faculties and faulty memory.”These words were intensely politically damaging to Biden, yet Hur did not worry that Biden lacked a legal forum to contest Hur’s assessment. He just said what he thought was true and in the public interest. Mueller refrained from such candor. It’s striking, on rereading the Mueller report, how absent Trump is from its pages. Mueller believed that he could not charge the president, so he refrained from even describing him.Mueller was a man who believed in the rule of law and the value of precedent, and he abided by an unspoken code of honor. He did not understand and so could not anticipate the moves of those who did not share his values or his code. He delivered his report on March 22, 2019, to Attorney General Bill Barr, who promptly released a letter proclaiming the total vindication of President Trump, then took 27 days before letting the public read a redacted version. (By contrast, the lapse between the delivery and public release of Hur’s report was only three days.)Mueller did not see it as his job to speak out—not then, nor in his notoriously faltering testimony to Congress months later. Mueller repeatedly referred questioners back to the text of his report, apparently unwilling—or unable—to add any words of his own. If his report was mischaracterized by Barr and Trump, Mueller did nothing to correct the record.[David Frum: What the Mueller report actually said]Despite the place Mueller once held in the public imagination, he did not see himself as an antagonist to Trump. At any rate, he was surely the least aggressive antagonist Trump has ever faced. So what can explain the posthumous malice Trump feels toward Mueller seven years after his investigation fizzled out? Perhaps it’s just the principle of the thing: For Trump, an enemy is an enemy and must be attacked by fair means or foul, even in the grave.But perhaps Trump’s grievance is more specific. The questions Mueller could not answer he also could not dispel. To this day, it remains clear that something is amiss in the relationship Trump has with Russian President Vladimir Putin. Trump in his second term has made it a priority to cut U.S. assistance to Ukraine and to coerce that struggling democracy to submit to Moscow’s terms. Might Trump’s pro-Russia policy in 2025 have anything to do with Russia’s pro-Trump policy in 2016?Mueller’s inability to get to the bottom of the murk did not make the murk any less murky. Trump seems to feel the suspicion to this day, and he’s right to feel it. But Robert Mueller is not to blame for this stain on Trump’s reputation. Trump did that himself.