Rahm Emanuel's interest in marijuana seemed to come out of nowhere. In truth, it was months in the making.

He'd been silent on the subject since tabling a proposal last fall that would ticket some possessors rather than haul them off to jail. Then, on June 15, he abruptly announced his support for a slightly tougher version of the plan. The announcement came from a safe distance—via press release, while he was in Europe for his daughter's bat mitzvah. And the issue was reframed to make the change more politically palatable: the proposal, Emanuel stated, "allows us to observe the law, while reducing the processing time for minor possession of marijuana—ultimately freeing up police officers for the street."

Within hours the story was international news, and within two weeks the new law was on the books. What remains to be seen is whether it will actually change anything.

The sudden passage of the law is the latest example of the absurdity surrounding marijuana policies and politics—an ongoing saga in which elected officials vow to crack down on a behavior that millions of Americans have engaged in, then giggle at their own jokes about getting stoned and getting the munchies. Not all of it is funny. As we reported last year, marijuana is believed to be used at similar rates across racial groups, yet African-Americans account for 78 percent of those arrested, 89 percent of those convicted, and 92 percent of those jailed for low-level possession in Chicago.

These arrests burden local courts, resulting in punishments meted out so capriciously that armed dealers are sometimes let off with little more than a slap on the wrist while casual users are locked up for possessing a dime bag. And though about 90 percent of these arrests are effectively thrown out in court, they cost county taxpayers at least $78 million and tens of thousands of police hours a year.

Even politicians long opposed to softening marijuana policies admit something needs to change. "The system is broken," says City Council dean Ed Burke.

Last fall, after our stories hit the street, Cook County board president Toni Preckwinkle and commissioner John Fritchey called on the city to reexamine its marijuana policies. At first only a few aldermen murmured their agreement, but eventually three joined Fritchey at a press conference to demand changes.

click to enlarge Alderman Danny Solis (25th), one of Emanuel's most loyal supportersJohn J. Kim/Sun-Times Media

John J. Kim / Sun-Times Media

To everyone's surprise, in strode Danny Solis, one of the mayor's most loyal supporters. And he didn't just show up: he announced plans to introduce his own proposal to the City Council to turn low-level pot possession into a ticketable offense. While the proposal still gave police the option of making arrests, it noted that "a disproportionate number of these arrests are of minorities" and proposed "a conversation among experts in health and public safety fields to gather data and information." Twenty-six other aldermen signed on as cosponsors.

The move was widely viewed as Emanuel's way of bogarting the issue from Preckwinkle and Fritchey. But Solis insists that he wasn't sent to crash Fritchey's press conference. "The mayor didn't want me to introduce this at all," he says.

What's undeniable, though, is that the issue belonged to the mayor from that point on.

Publicly the mayor told reporters that a cop had advised him to make some changes during a police ride-along, but he wanted time to "study" the issue. Privately Emanuel also needed to figure out where to stand politically. It took seven months. "Everything here moves slowly," says a mayoral aide.

Inside City Hall Emanuel made it clear that he was opposed to any move that would make him look soft on crime, the issue on which Chicagoans rate him lowest. He told aides that he wouldn't back any changes that could be characterized as "decriminalization"—but he might consider various "alternative sanctions," with an emphasis on the fact that police could still make arrests if they chose.

On the other hand, he didn't want to be left behind in what was obviously becoming a growing political trend. In addition to Preckwinkle and Fritchey, high-profile politicians in other cities and states were talking openly about pot while he was staying quiet. The most influential development came on June 4, when Governor Andrew Cuomo and Mayor Michael Bloomberg united behind a plan to expand New York state's decriminalization law as a way of reducing arrests in New York City.

Ultimately, though, another issue closer to home played a much bigger role in Emanuel's decision: a steady barrage of headlines about bloodshed in Chicago.

By the first of June shootings citywide were up 11 percent and murders 46 percent over 2011. Meanwhile, police superintendent Garry McCarthy was insisting to a group of downtown business leaders that the city's public safety problem was a matter of "perception" since overall crime totals were still going down.