As far as the rest of the country is concerned, Seattle is once again on its rightful path toward becoming an über-liberal paradise. In this edge-of-America place where City Hall throws open its doors for a grand festival of gay marriages and cops hand out Doritos to stoners at the local pot festival, our gay mayor just announced a proposal for a minimum wage more than twice that of the nation. Oh, yeah—and he did it on the morning of International Workers' Day, a few hours before the streets filled with diverse crowds advocating everything from an end to immigrant deportations to smash-the-state anarchy.

The Seattle wage-hike story made the front page of the Huffington Post and earned dueling think pieces in Slate and the Atlantic (Slate's was anti, the Atlantic's, written by a local wage-hike advocate, was pro). A piece in the UK Guardian was headlined "Seattle to debate $15 minimum wage law amid warnings of 'class warfare.'" The New York Times pointed out that Mayor Ed Murray's plan, "which in many other cities might be seen as a liberal Democratic agenda at the frontier of social and economic engineering," was, in this city, taking more heat from the left than the right.

That lefty heat, of course, was—and still is—coming from Seattle City Council member Kshama Sawant, whose election was, in itself, cause for an earlier round of national headlines, those focused on Seattle's history-making embrace of an unabashedly socialist candidate. It was arguably her November win that led to this minimum-wage moment of truth.

On May 1, when Mayor Murray announced his minimum-wage proposal at City Hall, hailing it as a compromise struck by members of a 24-person advisory committee that's been hashing it out since the beginning of the year, the plan was actually met with more confusion than outrage. A four-tiered proposal, phasing in different categories of employees to a $15 wage over seven years, and then taking another three for all the different categories to catch up to each other's inflation adjustments? It wasn't exactly the concise two-word demand for "15 Now" that we've heard from Sawant and seen on T-shirts and yard signs in Seattle all year.

Which is okay, says Sage Wilson, a spokesman for the labor-backed group Working Washington, which has campaigned with striking fast-food workers for higher wages since last spring. "A fast-food worker is not going to go on strike and demand a four-tiered wage schedule, right?" Wilson asks rhetorically. But this proposal, he continues, "is not a strike demand." Rather, it's an outline for a city ordinance. "The implementation of any law is complicated," Wilson says. And while the complications make understanding the whole plan seem difficult, its effects will be clear, according to Wilson. "Every single [low-wage worker] gets a substantial raise every single year," he says. "Everyone gets to $15. And everyone gets to a real minimum wage, with no deductions for tips or benefits."

So how, exactly, would this mayoral plan work? Let's break it down. (And if it helps, try looking at the chart above while we're breaking it down.)

• The mayor's proposal separates employers into two categories: large businesses with more than 500 employees and small businesses with 500 or fewer employees. (That includes employees nationwide, so most franchises should count as large businesses.)

• Everyone gets phased in to a $15 minimum wage, but how long the phase-in takes depends on what type of employer you work for.

• If you're an employee at a large business, like McDonald's, your minimum wage rises to $15 in 2017. (The purple line.) If you receive good-quality employer-provided health care, like Starbucks provides, your employer gets an extra year, so you'll hit $15 in 2018. (The orange line.)

• If you work for a small business or nonprofit, your minimum wage doesn't hit $15 until 2021. (The light blue line.) In the meantime, your employer is required to make sure that any tips or benefits you receive—or, if you don't get tips or benefits, your cash wages—add up to a grand total of $15 sooner, by 2019. (The green line.)

• When that first large-business category (the purple line) hits $15, the minimum wage of everyone in that category starts getting adjusted annually for inflation, with adjustments tied to the Consumer Price Index. Businesses in other categories will have to adjust a little faster than that once they hit $15, so that in 10 years, all categories will reach the same wage. (Seriously, look at the chart on this one.) The mayor's office projects that Seattle's minimum wage will be around $18 by then, though that depends on inflation.

• Also by that time, the counting of tips and benefits as compensation will completely phase out, so that by the time everyone reaches the same level of pay, no one's getting treated any differently.

Does that seem hard to wrap a brain around? Well, it is. It's the result of negotiations between 24 different members of the mayor's advisory committee in what amounted to a giant policy-making Jenga game—it's standing only because every little block is in the right place, an ever-so-complicated compromise.

A particularly interesting compromise centered on the question of how to count (and when not to count) tips and health-care benefits. It seemed like the labor side faced a tricky choice if they wanted support from the business side: either phase the small-business wage in over a long time, like seven years, or let small businesses count their employees' tips and benefits as part of the minimum wage. That second option, called "total compensation," was considered by labor to be a complete redefinition of what a minimum wage is. Right now, it's just the amount of money your employer pays you, with any benefits or tips added on top. If we raised the number, but changed what it meant, was that really a win?

The mayor's final plan is essentially a mix of both ideas, which was a big reason the divergent parties could agree. Counting tips and benefits during a transition period helps out employers, but phasing it out prevents a permanent precedent.

But it also adds to the complexity of the proposal, which will likely prove to be a problem when it comes to enforcement. The city council has already been warned by academics that the more complex a wage law, the harder it is to communicate that law to employers and employees alike. The more loopholes there are, the easier it is to not comply, either maliciously or by accident.

And that's not the only challenge the plan faces.

For all the hoopla around the mayor's announcement, it wasn't necessarily an announcement of anything. Sure, his personally appointed committee came to an agreement on what they think a minimum-wage law should look like, and the mayor's office will transmit legislation to the city council reflecting that. But the council, the city's legislative body, still has to pass it, and they've given themselves a month to tinker with the plan.

And while the individual members of the mayor's committee appeared to represent larger organizations that would be signing on to support a compromise, major players have now said their organization's members aren't necessarily on board. Maud Daudon, president of the Seattle Metropolitan Chamber of Commerce, abstained from voting on the mayor's proposal. Kshama Sawant voted no, and the activist group 15 Now has already filed a charter amendment that contains her simpler, quicker minimum-wage proposal (it would have big businesses paying a full $15 starting next year). David Watkins of the Seattle Hotel Association and Michael Wells of the Capitol Hill Chamber of Commerce have both signaled that while they voted for this proposal, members of their organizations still have concerns.

Which means that with a little lobbying, this whole thing could fall apart. At the first council meeting on the proposal, council members were already asking about tweaks to the deal that could very well tank the whole thing—like Council Members Sally Bagshaw and Tom Rasmussen, who brought up "training wages" for teens or entry-level workers, an idea that is popular with business owners and anathema to labor.

And opposite 15 Now, the business-backed group Forward Seattle plans to file an initiative representing a toned-down wage hike they think is more reasonable.

Sawant, for her part, is playing it cool. What's important right now, she says, is to fight against any further watering-down of the proposal by business groups and to fight for more progressive measures—e.g., a faster phase-in or not counting tips at all. But she keeps hinting that this proposal, as measured and complex as it is compared to hers, is still a big win for workers.

While she and fellow activists are ready to take their preferred plan all the way to the ballot, she said after the council's last meeting: "If the city council were to meet in the next 15 minutes and sign the [mayor's committee] proposal as-is, then we'd have to review that position." But, just like the business organizations, she notes that it's not all up to her—the decision on whether to go to the ballot will have to be made by 15 Now members.