Donald J. Trump keeps insisting that “there was no collusion.”

He does so repeatedly. With vigor. With passion. With emphasis.

My gut tells me the president is protesting far too much. He calls special counsel Robert Mueller’s investigation a “rigged witch hunt.” He says the allegations against his 2016 presidential campaign are “phony,” that they’re a “hoax” concocted by Democratic Party pols who are still sore at losing the election two years ago.

Let’s take a breather, shall we?

Mueller’s investigation is going to conclude eventually. I hope it’s soon. To that extent, I agree with the president that I want the probe to wind down sooner rather than later.

But … and this is critical: The investigation must be allowed to reach its conclusion under its own power.

Mueller is not the partisan hack that Trump and his allies accuse him of being. He is a dedicated public servant. He served as FBI director under two administrations, Republican and Democrat. He took office right after 9/11 and stayed on for a couple of years after George W. Bush left office; he served well under the Obama administration.

The president’s constant bitching about “witch hunts” and “phony” allegations ring hollow. It’s instructive that Mueller has imposed air-tight discipline on his legal team while Donald Trump’s team keeps yapping about “corrupt investigation” and threats of impeaching the deputy attorney general who appointed Mueller to the special counsel job.

I am aware that there’s nothing illegal about colluding with a foreign government. This investigation, though, won’t concern itself with whether anyone broke the law if they worked in tandem with Russian goons who attacked this country’s political system.

The public needs to focus also on whether it was right, presuming that Mueller’s team reaches that conclusion.

If the Trump campaign colluded with the Russians, then we’re going to witness the unraveling of an administration. The Mueller team will deliver its findings in due course.

If it determines there was no collusion, as the president insists, then I fear the tumult won’t subside. I am inclined to accept whatever conclusion Mueller reaches.

If only Americans could rely on Donald J. Trump to accept such findings and then move on. He won’t.

This much I know already: Robert Mueller is still hard at work seeking answers to questions that have lingered since the 2016 election. Let the man and his legal team finish their task.