For years, Portland's approach to camping enforcement has hardly been model of clarity. Despite the apparently strict wording of the city's anti-camping ordinance, banning things like blankets and sleeping bags, cops used personal discretion when deciding which sites (and people) to roust and which ones they'd ignore. At the same time lawsuits, including a years-long case settled last year that left the ban in place, tried to question the legality of the law in the first place.

And, notably, the law was not prominently invoked when Mayor Charlie Hales first tried to roust a nearly two-year-old camp outside city hall late last month. He tried to rely on the city's sidewalks law, until reporters reminded him that its provisions only carry during daytime hours.

But when that sweep backfired, merely spreading the camp to nearby streets, it was clear Hales had nowhere else to turn in the more than two weeks since his first push and the day he announced his newer, harsher crackdown. Whether he liked it or not, it was time to revive—and spruce up—the city's very controversial camping ordinance.

"The camping ordinance is a viable ordinance," Jim Hayden, the neighborhood prosecutor who helped advise the city's enforcement effort, says of discussions, "for many reasons," that led to Hales' move. "It can be used. Let's look at it."

The magic moment, behind the scenes, came when the police bureau and city began heeding something prosecutors had pointed out before, over the years, when declining to prosecute camping-related citations and arrests. To build a strong case, cops would need to show that someone wasn't just sleeping with their things outside. They'd need to show someone had established a "temporary residence," Hayden says.

That effort puts the emphasis on one what prosecutors, with a higher burden of proof than "probable cause," see as one of the stronger aspects of the camping law. It also requires documentation—of possessions, food, structures, how many days someone's been in the same spot, whether they go to the bathroom nearby, etc.—not discretion and whim.

"We weren't communicating as well as we could have been on that aspect of the camping ordinance," Hayden says. "We have all refocused on that aspect."

Hayden suggests hewing to a more deliberate standard—when handing out warnings and citations and, ultimately, arrests for failure to obey an officer's order to quit somewhere—is far more clear than the term of art "low impact" that cops still use when explaining how they approach camping enforcement. It also keeps from cracking down on someone sleeping.

The DA's office has also been working with Hales' team as part of the mayor's homelessness advisory group. Hayden attended a recent meeting in the place of the downtown neighborhood DA, Laurie Abraham, who has been on vacation and otherwise would have been working with the police on the camping issue. He says the subject of enforcement never came up at the meeting he attended, confirming what Hales' office told me yesterday.

The crackdown on camping—which Hales insists isn't about homelessness, even if it's far more explicitly tied to that issue than the behavior he first singled out this year, panhandling—hasn't gone down smoothly for activists and campers. But the DA's legal advice suggests a potential side benefit for anyone worried about mercurial cops and how they might use the discretion they've previously been given.

Says Hayden: "It's in the best interest of everyone to know what the rules are."