Now it's really getting serious: The fight for a $15 minimum wage in Seattle could be headed to the ballot box this year, instead of just churning through city hall.

For the last few months, the idea has been floated repeatedly by 15 Now, the organization backing a raise to $15 with a quick timeline and few loopholes. On April 14, at a city hall press conference, they announced real plans to take the fight straight to voters if politicians, scrambling to find a compromise between labor and business interests, produce a watered-down version of the wage hike. The threat to the mayor and city council is plain: Come up with a proposal that 15 Now's activists can support, or you'll face a ballot measure and a strenuous campaign to pass it this November.

And at their press conference, wage-hike activists started to make good on that threat.

With King County Council member Larry Gossett on hand talking about the importance of a $15 minimum wage for race and gender equity, and 15 Now activist and nurse practitioner Sarah White there to speak on the positive public-health impacts of addressing poverty, the newly formed campaign committee, called Vote 15, filed paperwork for a city charter amendment and signaled their intent to gather the nearly 31,000 signatures required to place it on the fall ballot.

Their ballot language, in a nutshell: Starting January 1, 2015, businesses with more than 250 full-time equivalent employees, along with franchise businesses, would have to raise their base wage to $15. For non-franchise businesses with fewer than 250 full-time employees, and for nonprofit organizations, the raise to $15 would happen over three years, starting at $11 in 2015.

Employers wouldn't be able to count things like tips, bonuses, commissions, or health care as part of their minimum-wage obligation (that's the "total compensation" idea that business interests have proposed). The wage would also be indexed to inflation, just like the state's minimum wage. And provisions to educate workers and further penalize wage theft by employers would be included, too.

Because it's not exactly a surprise, responses so far have been rather muted. "I think it was expected that this would happen," said Alex Fryer, spokesman for the business-backed OneSeattle Coalition. The mayor simply said in a statement that he remains "committed to making progress on this issue through the stakeholder process" (meaning: his advisory committee on the matter).

For now, there's no guarantee this measure will go all the way to the November ballot. Philip Locker, a 15 Now organizer, called the charter amendment a "backup plan" and a "fail-safe mechanism." "We're practical people," he continued. "We don't want to waste our time and energy on a November election if the city council will pass an adequate $15 minimum wage."

But that's not to say they won't if they feel they have to: A February poll showed a vast majority of Seattle voters—68 percent—support a quick, clean raise to $15, and 15 Now has certainly demonstrated their political organizing and fundraising abilities this year. They'll likely decide in June whether to go all the way.

There's just one catch: They're not the only ones keeping a ballot option open.

"Would there be a potential for us to go to the ballot with a proposal of our own? It's very possible," said Fryer of OneSeattle. He said it's too soon to talk specifics, but they'd likely include a phase-in for everyone, training or youth wages, and consideration of total compensation. "We'll see how it goes," Fryer said, referring to the ongoing, closed-door discussions of the mayor's advisory committee.

That committee has one more meeting this month, and sources say the sides appear to be deadlocked over total compensation.

Tick-tock.