Special counsel Robert Mueller III departs St. John's Episcopal Church on March 24 in Washington. (Tasos Katopodis/Getty Images)
Nicole Hemmer is an assistant professor at the University of Virginia's Miller Center and author of "Messengers of the Right: Conservative Media and the Transformation of American Politics." She is a co-editor of The Post's daily historical analysis section, Made by History.

Anyone who had been holding out hope that the completion of the report by special counsel Robert S. Mueller III would signal the beginning of the end of the Trump presidency has had a pretty rough 24 hours. The banner headline for Monday’s print edition of The Washington Post sums it up: “Mueller finds no conspiracy.” Although the full report — unreleased — may not be as friendly to the Trump administration as Attorney General William P. Barr’s four-page summary, President Trump seems to have survived Mueller’s report. For all the time and money spent on the investigation, it ultimately failed.

Or so it seemed to some Americans convinced that members of the Trump campaign and administration, right to the very top, committed crimes and impeachable offenses. But the Mueller investigation was far from a failure. It only looks that way because we are so wedded to viewing alleged political wrongdoing through the lens of Watergate.

Seen through the lens of another scandal, the Iran-contra affair, the Mueller investigation looks very different: It produced impressive documentation of malfeasance, including numerous indictments.

In both instances, an irreproachable special prosecutor assiduously documented evidence of lawbreaking throughout a president’s inner circle, sent people to prison and left a detailed, damning record for history. And while Ronald Reagan and his vice president, George H.W. Bush, escaped indictments — just as Trump seems to have escaped a finding that he obstructed justice — very few people think the Iran-contra report vindicated Reagan.

To summarize: Over the past two years, Mueller sorted through the complex story of Russian interference in the 2016 election. Not only did he conclude that a foreign power indeed interfered in the race, Mueller also secured indictments against 34 people, including six members of the Trump campaign in both financial and election-related cases, with charges ranging from conspiracy to obstruction to making false statements to witness tampering. Everyone within U.S. jurisdiction who was indicted by Mueller has been found guilty or has pleaded guilty except for Trump campaign adviser Roger Stone, who is awaiting trial. (Mueller also charged 26 Russians in crimes including conspiracy to defraud the United States and aggravated identity theft; they remain at large.)

Compare that to the nearly-seven-year investigation — 1986 to 1993 — of independent counsel Lawrence Walsh into Iran-contra, a wide-ranging criminal conspiracy perpetrated by the Reagan administration that involved millions of dollars in arms sales to Iran, a country then under an international arms embargo; in exchange, Iran released seven U.S. hostages. A chunk of the proceeds was then diverted to the contra, right-wing rebels working to overthrow the Nicaraguan government. That part was illegal, too: Congress had explicitly banned any aid to the contra rebels in laws passed between 1982 and 1985.

Yet as complex as the operation was, and as hard as those involved stonewalled and obstructed the investigation — down to destroying evidence — Walsh managed to piece together the sprawling international plot. He secured indictments against 14 people, including the secretary of defense, Caspar Weinberger; two national security advisers, Robert McFarlane and John Poindexter; and the assistant secretary of state, Elliott Abrams, on charges including conspiracy, obstruction and perjury. Eleven of the 14 were convicted.

Reagan and Bush were heavily implicated in the investigation, though Walsh opted not to indict them (in part because Bush failed to hand over evidence, and in part because Department of Justice guidelines advise that a sitting president cannot be indicted). Reagan constructed an artifice of plausible deniability. In a 1990 deposition, he said, “I can’t remember” or “I don’t recall” 88 times. But Americans didn’t believe these denials — only 14 percent said they thought Reagan knew nothing about the illegal arms deal.

So Walsh, it is true, did not bring down a president; nor did he bring charges against a president. And then, as now, partisans complained that Walsh was engaged in an expensive witch hunt. It’s also the case that voters did not hold these charges against the Republicans, at least not at first. Reagan finished his second term with the highest approval ratings of any post-World War II president. Bush was elected president, and, in brazen pardons in his final days in office, Bush wiped the record clean for six of those indicted, including Weinberger (who was awaiting trial), and McFarlane and Abrams (who had both been convicted).

But while executive maneuvering overturned Walsh’s convictions, it could not erase his findings. After the pardons, Walsh published a book about the investigations called “Firewall: The Iran-Contra Conspiracy and Cover-Up,” in which he argued that the Bush pardons had been the final act in a criminal conspiracy that spanned two administrations. Through his report, and also through that book, he ensured that Americans would be able to learn the details of what was, at the time, the gravest political scandal of the modern era.

We don’t know whether Trump will survive the many scandals of his administration; the U.S. attorney for the Southern District of New York is investigating Trump’s business dealings, among other matters. It does seem likely the president will survive the Mueller report. But that’s not the best measure of a special counsel’s work. Just as Walsh exposed the corruption and lawlessness within the Reagan and Bush administrations, Mueller has demonstrated that Trump’s campaign was riddled with Russian contacts and criminality.

What Congress and, ultimately, voters decide to do with that information will determine Trump’s fate. But thanks to Mueller’s work, the historical record will reflect the foreign interference and mercenary corruption at the heart of the 2016 election. That’s an achievement not to be dismissed lightly, even if the investigation didn’t end in the definitive fashion many on the left were expecting.