AMAZINGLY, after three months, the sticky labor negotiations between Portland's main police union and a team of city negotiators remain out in public view—and with both teams still cracking jokes and jawboning awkwardly during their near-weekly huddles.

That casual bonhomie arises, in part, because no matter which side you look at—management or union—you'll find veteran cops who still have more in common with themselves than any outsiders. The same goes somewhat for the two professional negotiators, the city's Steve Herron and the Portland Police Association's Will Aitchison, both of whom also speak a peculiar common language, of contract parlance and precedent.

It conjures cartoon memories of wolves and sheepdogs: foes at work, pals once the whistle blows.

But while the sides, so far, have maintained their willingness to keep bargaining out in the open, right where we can see 'em, fault lines are looming that may drive them into a mediator's care. Away from the public's prying eyes.

And that could mean an uncertain future for some of the most important elements at stake in the negotiations: civilian oversight and drug testing.

For instance, even as the city holds firm on its call to sharply limit cops' pay raises for the first two years of the contract, it has softened its plan to gut a long-held perk that lets cops exchange overtime pay for time off.

Aitchison, at the last negotiating session, December 10, decidedly wasn't joking when he threatened over that issue: "You can't push us too far."

Because the city, still treading uncertain budget waters, needs to squeeze as much savings as it can, it has been loath to press for other changes that would inflame the union. Like giving civilian investigators the power to directly question cops who misuse force—a longtime goal of the police reform community.

Similarly, Herron also announced the city was "working on" its proposal to subject sworn officers to random drug-and-alcohol tests—a notion trumpeted by Mayor Sam Adams but strongly contested by the union—in part to keep them at the table.

The two sides have until mid-February before one can unilaterally tell the other to screw off, so to speak, and demand mediation. Of course, if both camps agree it's time to duck away, they can do it tomorrow. That seems unlikely, given the tone of the talks so far. But remember this: One day, the laughter will end.