When former Special Counsel Robert Mueller testifies July 17 before two Democratic-controlled House committees about his investigation of Russian interference in our 2016 presidential election and possible obstruction of justice by President Trump, Mueller should refuse to say anything about the investigation of Trump and his campaign beyond what is already in his report.

Reps. Jerrold Nadler, D-N.Y., and Adam Schiff, D-Calif., announced Tuesday that Mueller has agreed to testify before the House Judiciary Committee and House Intelligence Committee after the Democratic-controlled committees subpoenaed him.

If Mueller goes beyond his 448-page report he will commit the same sin for which then-FBI Director James Comey was rightly condemned when Comey went further than a prosecutor should ever go in public after making a decision not to charge a crime.

ROBERT MUELLER AGREES TO TESTIFY BEFORE HOUSE LAWMAKERS JULY 17 AFTER SUBPOENA, NADLER AND SCHIFF ANNOUNCE

In 2016 Comey held an outrageous news conference that dealt with the FBI investigation of Hillary Clinton’s handling of emails when she served as President Barack Obama’s secretary of state.

Instead of simply saying there was not enough evidence to prosecute the then-Democratic presidential nominee, Comey expressed his opinion that Clinton was “extremely careless” about her handling of State Department emails on her private server.

The same principle that should have kept Comey from talking about the Clinton emails should severely limit what Mueller can say about his investigation of Trump and his campaign.

The long tradition of the Justice Department – backed by important policies, including the presumption of innocence for anyone suspected of wrongdoing – is that law enforcement officials should only comment if someone is charged with a crime.

If a decision has been made not to charge someone with a crime, law enforcement officials should never comment beyond stating that simple fact.

So Democrats should be careful about what they’re asking for. It may turn out that Mueller’s House testimony will backfire against the Democrats and help the Republicans.

Comey violated that sound tradition when – after announcing that Hillary Clinton would not be charged in relation to her private server – he expressed his opinion that she had been extremely sloppy in her handling of emails, some of which were classified.

To avoid repeating Comey’s mistake, Mueller should refuse to go beyond his report and should not express any opinion in his congressional testimony regarding possible criminal conduct by President Trump – no matter how hard Democrats try to get him to do so.

This is true whether or not Mueller believes that a sitting president can or cannot be charged with a crime under Justice Department policy.

It is not the job of a prosecutor to decide guilt or innocence. That is the job of a jury or judge, after hearing and seeing all the evidence – including that presented by the defense.

Any prosecutor – including a special counsel like Mueller – hears only one side. Based on that one-sided review only of evidence unfavorable to the accused, the prosecutor must decide whether that evidence – if believed – constitutes probable cause that a crime was committed by the person under investigation.

Of critical importance, the prosecutor does not decide whether the accused is guilty beyond a reasonable doubt. A decision that there is enough evidence to prosecute a person does not erase the presumption of innocence that we are all entitled to under the Constitution.

Nor should a special counsel undercut the presumption of innocence by suggesting that a person who he has decided not to prosecute may possibly be guilty.

The irony of the Democratic subpoena directed at Mueller is that while he may not properly answer the kinds of questions Democrats would like him to answers – namely regarding possible evidence of wrongdoing by President Trump – the former special counsel can properly answer the kinds of questions Republicans would like to ask him, so long as this doesn’t require the disclosure of classified or other privileged information.

The Republican questions could involve the so-called Steele dossier – a report making unproven charges about Trump written by a former British spy and funded by the Clinton campaign. Republicans could also ask about possible misrepresentations made by federal officials to the Foreign Intelligence Surveillance Court that allowed the initial FBI investigation of the Trump campaign to begin, along with other issues that were not the subject of the Mueller investigation or report.

So Democrats should be careful about what they’re asking for. It may turn out that Mueller’s House testimony will backfire against the Democrats and help the Republicans.

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The real victims of the Democratic attempt to politicize the criminal justice system are ordinary Americans. If House Democrats can demand that Mueller testify about his investigation, then any congressional committee can subpoena any prosecutor who declines to prosecute any ordinary American. This would establish a terrible precedent that would undercut the rule of law.

For these reasons, Democrats and Republicans alike should oppose all efforts to undercut the long tradition of prosecutorial silence when a decision has been made not to prosecute.

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