Special counsel Robert Mueller’s investigation into Russian interference in the 2016 election and related matters turns one year old Thursday, and Republicans are simply disgusted that it could have dragged on this long. Their position is summed up by the president:


Donald J. Trump tweeted “Congratulations America, we are now into the second year of the greatest Witch Hunt in American History…and there is still No Collusion and No Obstruction. The only Collusion was that done by Democrats who were unable to win an Election despite the spending of far more money!”


As President Trump’s crackerjack lawyer Rudy Giuliani put it on Fox: “It’s about time to get the darn thing over with. It’s about time to say, ‘Enough. We’ve tortured this president enough.’”


The truth, however, is that Mueller’s investigation has been both fruitful and efficient compared with many similar investigations of administration officials. To make that clear, let me offer you a selection of prior investigations conducted by independent and special counsels, along with the length of time they took to conclude:


—Iran-Contra: 6 years, 8 months (1986-1993)


—Samuel Pierce, HUD corruption: 9 years (1990-1999)


—Bush administration, improper search of passport records: 3 years (1992-1995)


—Henry Cisneros, mistress payments: 11 years (1995-2006)


—Mike Espy, gifts from agriculture company: 6 years (1994-2001)


—Bill and Hillary Clinton, Whitewater: 6 years 8 months (1994-2000)


—Scooter Libby, CIA leak: 3 1/2 years (2003-2007)


In all these cases, people complained that the investigations went on too long, and they were often right. But some of them certainly warranted a lengthy investigation. Iran-Contra was a sweeping conspiracy involving multiple crimes committed by multiple people in the Reagan administration, in which arms were sold to Iran and the profits taken to fund an illegal proxy war in Central America. Even if almost seven years was too long, it would have been ridiculous to suggest that a single year would have been enough.


Other investigations were absurdly lengthy given what they were investigating; for instance, HUD secretary Henry Cisneros lied to the FBI during his background check about money he had paid to his mistress, which was indeed against the law but hardly warranted an investigation that went through multiple phases and wasn’t completely closed for 11 years.


But no one is suggesting that Mueller will need another 10 years to get to the bottom of the Trump omni-scandal. Informed observers looking from the outside believe that he’ll be finished by the end of this year or the beginning of next year, meaning the whole thing will be wrapped up in less than two years.


One of the most important things to remember about Mueller’s critics is that, like all of us, they have only a general sense of what Mueller has been doing. His investigation has been leakproof; whenever we learn something about it, it’s via someone who has testified to the grand jury or the substance of court filings. There’s zero indication that Mueller has been anything but thorough and professional, which is exactly why he, a lifelong Republican and widely respected law enforcement official, was picked for the job.


Now let’s do a quick rundown of what Mueller has so far produced:


—An indictment of 13 individuals and 3 companies in connection with Russian efforts to infiltrate and manipulate the 2016 election.


—Indictments on multiple charges against former Trump campaign chairman Paul Manafort.


—Guilty pleas from former Trump aides Michael Flynn, Rick Gates, and George Papadopoulos, offered in exchange for their cooperation.


—Guilty pleas from two other figures, Alex van der Zwaan and Richard Pinedo, tangentially connected to the original investigation.


There is obviously much more on its way.


We have to remind ourselves of the scale of what Mueller has to investigate. It starts with the fact that a hostile foreign government mounted a comprehensive effort to swing the results of an American election. That we have to actually argue about whether or not that is a big deal is utterly insane. Then there are Trump’s efforts to obstruct justice, for which there is ample evidence. Then you move to the other potential crimes the investigation has uncovered along the way, like Paul Manafort’s alleged money-laundering and Michael Cohen’s Trump Tower-sized pile of potential crimes. Given what we know and what we’re learning literally on a daily basis, nobody sincerely thinks that Manafort and Cohen aren’t going to wind up behind bars.


When it comes to Cohen in particular, his misdeeds keep leading back to Trump. The fact that Trump has now admitted that he lied about what he knew about the hush money Cohen arranged for Stormy Daniels is just the tip of a very dirty iceberg, a colorful illustration of the fact that we have only the barest idea what the investigation will uncover about the Trump Organization and Trump himself. The president may be the single most corrupt prominent business figure in America, and once prosecutors start examining that business, they’re going to have a lot of work to do.


So no, this investigation hasn’t gone on too long. All indications are that Mueller is moving with all appropriate speed; the trouble is that there’s just so much potential malfeasance to examine. And no amount of hand-waving from Rudy Giuliani or cries of “Witch hunt!” from the president will change that.


Paul Waldman is a columnist with The Washington Post.