The Justice Department inspector general’s report on the FBI’s 2016 handling of the Clinton email investigation has reenergized those arguing that special counsel Robert S. Mueller III’s investigation is illegitimate. President Trump’s lawyer Rudolph W. Giuliani recently claimed that Mueller’s investigation is likely to be “thrown out” because of alleged FBI misconduct revealed in the report. A recent Wall Street Journal op-ed co-authored by former Reagan and George H.W. Bush administration attorney David B. Rivkin Jr. — and retweeted by the president — argued that the report demonstrates that Mueller’s investigation is tainted by bias in its origin and should be shut down as “fruit of the poisonous tree.”

The hypocrisy is evident: Conservatives typically decry judge-made doctrines such as “fruit of the poisonous tree” as “technicalities” that allow the guilty to walk free. And a president who has shown little regard for due process for others, such as those arriving at our borders, is quick to embrace it when it comes to investigations of his own behavior.

But irony aside, it’s worth examining how frivolous this “taint” argument is, both factually and legally.

The main villain in the supposed conspiracy to topple Trump is FBI Deputy Assistant Director of Counterintelligence Peter Strzok, who worked on both the Clinton email investigation and the Russia investigation. Strzok and then-girlfriend Lisa Page, an FBI attorney at the time, exchanged a number of ill-advised text messages expressing anti-Trump sentiments.

But these personal exchanges can’t bear anything close to the weight Trump’s supporters seek to place on them. Inspector General Michael E. Horowitz’s report also found no evidence that any actions by Strzok or the FBI stemmed from personal bias or political motivation. And Strzok was not working alone; he had colleagues and supervisors. The notion that a single agent could bend the entire Justice Department investigative leviathan to his will — particularly in such a significant case — is ludicrous.

Then there’s the fact that, prior to the election, information about the Russia probe was kept secret while FBI personnel were publicly commenting on and leaking widely about the Clinton email investigation. Apparently Trump’s supporters believe that, when it comes to rigging an election, the FBI is not merely corrupt but also incompetent.

Strzok has long since been booted off the Russia probe. Since Mueller was appointed, there have been 19 indictments and five guilty pleas. There are reports of more than a dozen people affiliated with the Trump campaign who had contacts with various Russian individuals in the months leading up to the election. More than a dozen prosecutors have been working with numerous FBI agents investigating the various charges, and their actions have been repeatedly upheld by independent judges. These results already belie any claim there was no proper basis for an investigation — and Mueller’s not done yet.

So what exactly do one FBI agent’s personal text messages to his girlfriend nearly two years ago have to do with the facts of this investigation?

As for the legal theory, “fruit of the poisonous tree” is a rule that excludes evidence resulting from an investigator’s unlawful act, such as an unconstitutional search or arrest. Even when there is such misconduct, if the connection is too attenuated or the evidence would have been discovered anyway the doctrine doesn’t apply. But the inspector general found no unlawful investigative acts here; you can’t have tainted fruit if there’s no poisonous tree in the first place. And the authors of the Journal op-ed are arguing not to keep out particular items of evidence but to torpedo an entire investigation, despite nearly two years of intervening events and independent actions by other investigators. That’s not discarding particular pieces of fruit. That’s uprooting the entire orchard.

If those ultimately charged by Mueller want to make a “fruit of the poisonous tree” claim to a judge, they should do so. I’m confident they’ll be laughed out of court. But claiming the doctrine should be used to end Mueller’s entire investigation is just political grandstanding, not a serious legal argument.

Those who argue Mueller’s probe is “tainted” no longer bother to deny there was Russian interference with the election or possible collaboration by members of the Trump campaign. Instead, they argue there is no “public evidence” of such a conspiracy (yes, exactly — that’s the way grand jury secrecy works) and simultaneously claim the investigation that could ultimately reveal such evidence should be halted.

The IG report provides no basis for impugning Mueller’s inquiry. But the fact that Trump and his supporters would seek to use such a slender reed as a pretext to shut it down can’t help but leave you wondering what they fear Mueller will find.