The circus is coming to town and the carnival barkers are working up a sweat trying to spark interest. So far, ticket sales are slow.

Robert Mueller is slated to appear in Washington’s Big Tent Wednesday when he testifies to two House committees. The former special counsel threw a wet blanket on expectations by vowing he wouldn’t say anything beyond what’s in his report, but the hype machine still promises a sensational show.

Naturally, the anti-Trump media are doing their best to pump oxygen into the dead-of-summer event, with NBC News running this screaming headline on a setup article: “Mueller hearings to highlight ‘shocking evidence of criminal misconduct by Trump,’ Democrats say.”

But the bombshells quickly proved to be duds. In the second paragraph, the “Democrats” turned out to be an anonymous ­Judiciary committee staff worker — not even a member of Congress! — saying “It is not that that there will be a big, dramatic new revelation necessarily, we’re not expecting that.”

The staffer went on to suggest that the “shocking evidence” is already known because of Mueller’s report and that Dems would make the case that “any other American” would have been indicted.

In other words, the promised revelation of “criminal misconduct” boils down to partisan spin of the report. This is not news, and the only shock is that NBC would so foolishly pretend otherwise.

Certainly the Democrats’ newest plan to smear President Trump is not news after more than two years of leftist obsession with Russia, Russia, Russia collusion and accusations that Trump was a traitor. When they proved to be damnably false charges, the accusers switched ­focus to insist he committed obstruction of justice and would be frog-marched in handcuffs out of the White House.

Given that Mueller didn’t recommend any criminal charges, the only news is that Dems refuse to give up on their fantasies.

Maybe a team of psychiatrists should be summoned to explain an obsession that is a break with American government norms and reality. The shrinks could tell us why the left can’t accept that Trump won the 2016 election fair and square.

A second anonymous staff member, from the Intelligence Committee, tried to pump life into that panel’s scheduled two hours. This one told NBC sleuths that members would focus on the “actual evidence” Mueller found because it “has not received the attention it’s due.”

In fact, all the evidence has gotten more attention than it deserved, given the absence of charges. The verdict is complete: Not guilty.

Similarly, the two committee chairs, Rep. Jerry Nadler of Judiciary and Rep. Adam Schiff of ­Intelligence, have gotten more ­attention than they deserve. Schiff was a media favorite during the Mueller years with his repeated assertions that there was compelling evidence that Trump engaged in collusion.

In a better world, he’d now be ashamed to show his face except for appearances on the Comedy Channel. But in Congress, with its 20 percent approval rating, he’s still a star.

The biggest pre-hearing dispute was over whether all 41 Judiciary members would get a chance to ask Mueller a question. They all demanded equal shares of political oxygen, also known as TV air time.

That couldn’t happen under the scheduled two hours so an extra hour was added. By my count, that means each member will get

4 minutes and 39 seconds — assuming nobody talks too long and Mueller keeps his answers short. I expect some nasty clock drama, which could be the day’s highlight.

That’s not to say there aren’t potentially high stakes. For Dems, the combined five hours will be their last, big chance to convince the general public that Trump should be impeached.

Speaker Nancy Pelosi has held back the wing nuts, knowing that the GOP-controlled Senate will not convict and that a failed move to oust the president could be ­political suicide in 2020.

Her problem is that while most polls show the majority of Americans say no to impeachment, as many as 67 percent of national Dems say yes.

Her strategy of letting the ­impeachment caucus investigate in hopes of pushing up general public support hasn’t substantially moved the needle. That leaves the Dems desperate for Mueller to give them something new, even a stray sentence or two, that they can spin into a web of impeachment.

Keep that desperation in mind as Nadler, Schiff and others fulminate and make outlandish charges in hopes of gaining support for the decisions they’ve already made.

On the whole, Republicans would rather Mueller not testify because Trump and the party have little to gain. But some in the GOP nonetheless are eager to get Mueller under oath so they can ask pointed questions about things his report doesn’t address.

These include how he came to appoint so many agents and prosecutors who had connections to or supported Hillary Clinton. And why, when he removed FBI agent Peter Strzok after learning of his anti-Trump texts, Mueller never said anything publicly.

Other issues concern why Mueller used predawn raids of heavily armed agents against Paul Mana­fort and Roger Stone. And when exactly did Mueller conclude there was no collusion? Was it before the 2018 midterm elections, when Dems took control of the House?

My guess is that the long day will be like so many other hearings during the Trump presidency. There will be lots of shouting, acrimony and histrionics but when the TV lights are turned off, nothing will have changed.

For Dems, that would be a nightmare. For America, a blessing.

The last thing the nation needs is a polarizing push for impeachment. Mueller’s fishing expedition lasted two years and it’s time to put aside the partisan nonsense and get on with the business of America.

Hey, you 1st, Beto

Texas presidential candidate Beto O’Rourke has gone from force to farce. His latest stunt is to restate his support for reparations by declaring that he and his wife are the descendants of slave owners.

Reparations are not likely to become federal policy, but that doesn’t mean there is nothing he can do. O’Rourke should set an example: he and his wife can give part of their vast wealth to the descendants of their families’ slaves.

That would be proof of his sincerity, a virtue not often associated with O’Rourke.

Left dusts off Zionism trope

Backwards, march.

From 1975 until 1991, the United Nations operated under an odious resolution that declared “Zionism is a form of racism.”

Last week, jewishinsider.com reported that “T-shirts linking Zionism with racism” were being sold at the far-left Netroots Nation conference in Philadelphia

Sanity eludes liberals

My column on how Ed Koch worked with President Ronald Reagan and other Republicans to get things done for New York, in contrast to our current crop of Dems, rang a bell with reader Donald Nawi. Using words Koch used to describe himself, Nawi writes that the late mayor “belonged to a species that is not just endangered but extinct: A liberal with sanity.”