Politics and government contracting aren’t supposed to mix.

But this is Chicago, the city of Hired Trucks and the Duffs and the former public schools CEO now in federal prison for demanding a 10 percent cut of a $20 million insider deal.

And for most of the city’s history ­— even on many deals in which no public officials were caught taking bribes — the attitude could be summed up pretty well like this:

What good would it do me to have power if I can’t hire my friends’ companies and let them dip their beaks into the endless stream of taxpayer dollars?

OPINION

Now, as Mayor Rahm Emanuel approaches the last year of his second term — and apparently wants voters to give him another four years — we have two developments to ponder:

  •       Emanuel’s former top cop, Garry McCarthy, is loudly mulling a campaign against him in the election that’s just a little over a year away.
  •       Emanuel’s administration is re-bidding the highly lucrative O’Hare janitorial contract, which has earned well over $100 million for the company led by McCarthy’s buddy and former business associate Rick Simon.

Emanuel bounced McCarthy from his job as Chicago Police superintendent in 2015, shortly after the release of a video showing cops firing 16 bullets into 17-year-old Laquan McDonald.

McCarthy quickly found a soft landing with Simon, a former cop he became friends with after arriving in Chicago in 2011.

In early 2016, McCarthy opened up his new business in the South Loop building owned by Simon.  It’s the same building where Simon’s United Maintenance Co. Inc. is based.

Despite heated union opposition, the company had won a five-year deal to clean the terminals of O’Hare Airport in 2012. That deal recently expired, though United Maintenance continues to work at the airport under a contract extension.

Five years ago, when they chose Simon’s company for the O’Hare work, city officials said they could have cancelled the deal after the Sun-Times reported that the firm failed to disclose all of its investors, as was required under the contract. But Emanuel aides decided not to cite that clause and they let the deal go forward over objections from some union-allied aldermen.

Emanuel administration officials said this week they plan to put the deal out to bid soon, right after they close deals with the airlines that will have gates at the expanded O’Hare.

The expansion means that the next janitorial deal will be an even bigger one than the current contract — under which the city has paid United Maintenance at total of

$105.6 million through Jan. 12, according to public records.

It’s a very big number to just float out there, totally adrift from the intrigues of a developing field of mayoral candidates.

Weary watchers of Chicago politics will speculate that the mayor’s office can use the potential deal as leverage to try to force McCarthy from the race.

Some City Hall skeptics also are wondering whether McCarthy is threatening to run in an effort to help his friend keep his O’Hare work.

McCarthy didn’t return my messages.

Simon said McCarthy’s company moved out of his building a while ago.

“He was a tenant in the building and that was it,” Simon said. “He did some consulting work for us, but he hasn’t done that in a year or two. At least a year.”

Simon added that he wants to keep the O’Hare deal:  “When they put it out to bid, we would intend to re-bid for it.”

Asked about the confluence of events, an Emanuel aide said officials would choose the lowest qualified bid, and the mayor would have no involvement in the selection of the next O’Hare janitorial contractor.

The bigger problem for McCarthy’s mayoral bid may be his connections to President Donald Trump, who once called McCarthy a “phenomenal guy.”

Trump got less than 13 percent of the vote in Chicago in the 2016 election. And it’s possible he’s even less popular now, after repeatedly calling Chicago everything but a s——- city during his first year in the White House.

Asked last month if he voted for Trump, McCarthy told NBC5 Chicago, “I don’t think it’s anybody’s business.”

Emanuel’s well-funded re-election campaign surely will try to use those ties to the mayor’s full advantage.

“Garry McCarthy and Richie Simon should just move their offices to the Trump Tower, maybe open a campaign office there, too,” said Emanuel’s campaign spokesman, Pete Giangreco. “That would take care of Garry and his two most important friends.”

If McCarthy decides to run for mayor, we could learn just how toxic any sort of association with Trump is to a candidate in this deep-blue town.

By then, we also should know if McCarthy’s friend will continue to rake in the green at O’Hare.