Trump Russia Probe Lawyers (copy) (copy)

FILE - In this June 21, 2017, file photo former FBI Director Robert Mueller, the special counsel probing Russian interference in the 2016 election, arrives on Capitol Hill for a closed door meeting before the Senate Judiciary Committee in Washington. (AP Photo/Andrew Harnik, File)

Time is running out for special counsel Robert Mueller’s investigation into alleged collusion or conspiracy between Donald Trump’s presidential campaign and the Russian government in 2016, and the firing of FBI Director James Comey in 2017. He should wrap it up this month.

Political tradition holds that the general election season begins on Labor Day, now about three weeks off. The Justice Department has usually required prosecutors to produce any findings in a case that might have an influence on the election as early as possible before that time or to suspend their work and go silent until after the election.

One of the many irregularities that led to Mr. Comey’s firing was his reopening of the case of Hillary Clinton’s emails a few days before the 2016 presidential election.

Because of the intense interest in Mr. Mueller’s investigation, it is unlikely he can successfully put things on hold until after the November election. Leaks have characterized the entire course of the collusion probe, and there is little reason to believe that Mr. Mueller will be able to sustain effective silence in coming weeks.

The best course of action is to wrap it up as soon as possible.

The major pending question in the investigation is whether Mr. Trump will allow himself to be questioned by investigators with the power to charge him with making false statements. There are legal arguments that the president is not obliged to submit to interrogation, but Mr. Trump has wisely said he wants to be interviewed by Mr. Mueller.

News reports say there is disagreement between Mr. Trump’s lawyers and Mr. Mueller on the questions the president will be asked to answer. Mr. Trump’s attorneys have said he is ready to answer questions on the collusion or conspiracy issue. But he reportedly declines to be questioned about his firing of Mr. Comey, his contradictory statements about the firing and his criticism of Attorney General Jeff Sessions for recusing himself from the Russia probe.

Some reports say Mr. Mueller is seeking evidence that the president’s motive was to obstruct the Russia probe. But his lawyers say he was acting within his constitutional powers in replacing Mr. Comey, and that cannot be the basis of a charge of obstruction of justice.

Because Mr. Trump is given to making contradictory statements on many issues, he clearly runs a risk if he has to face a skilled and determined prosecutor. While there is no credible reason to think that Mr. Mueller will behave in a predatory or unprofessional manner, it is only prudent for the president’s lawyers to object to that line of questioning.

Indeed, there is reason to think that, despite Mr. Trump’s frequent and deplorable denunciation of the Mueller probe as a “witch hunt,” there has actually been a lot of quiet cooperation between the president and Mr. Mueller. For example, the special counsel had to obtain the president’s permission to declassify sensitive intelligence information in order to indict eight Russian intelligence officers for hacking Democratic Party emails in 2016.

With election season looming, Mr. Mueller has an obligation at this time to put up or shut up. And he should exercise discretion if he wants Mr. Trump’s cooperation, which he needs to bring the collusion portion of his probe to a speedy end.