Rob Kampia thinks so, and he's a very well-placed observer. As head of the Marijuana Policy Project, Kampia has his finger on the pulse of pot politics as well as anyone, and he made a pretty startling prediction at the International Drug Reform Conference in suburban Washington last weekend.

At a panel on "Marijuana Reform in Congress," Kampia suggested that a handful of state-level marijuana legalization victories next year is going to set in motion a congressional debate on legalization that could see an end to federal marijuana prohibition before the end of the decade.

Legalization campaigns are already well-advanced in Arizona, California, Maine, Massachusetts, and Nevada, and while getting on the ballot is no guarantee of victory next November, polling so far suggests that most of them will win. And next year could also be the year the first state, and even perhaps a second, legalizes it through the legislative process.

"If you look at what's about to happen," Kampia said, "Vermont is most likely to legalize through the legislature, and Rhode Island has a good shot, but those are the only two states in play."

But then there are the initiative states.

"It could be that four or five initiative states legalize it, and then all of this is facing Congress in 2017," Kampia continued. "Then there will be a vigorous debate on legalization, and then, I predict, Congress could pass the states' rights bill in 2019."

Kampia is talking about something along the lines of this year's Respect State Marijuana Laws Act of 2015 (HR 1940), sponsored by Rep. Dana Rohrabacher (R-CA), which would amend the Controlled Substances Act (CSA) so that it would not apply to persons in compliance with marijuana laws in their state.

Passage of such a bill would not make marijuana legal everywhere—that would be up to the individual states—but would end the federal government's role in enforcing marijuana prohibition.

Kampia even suggested that Congress might get around to passing a bill to end federal pot prohibition before it gets around to passing a bill allowing states to enact medical marijuana laws without federal interference. That means legislation similar to this year's Compassionate Access, Research Expansion, and Respect States (CARERS) Act of 2015 (S 683), sponsored by Sens. Cory Booker (D-NJ), Kirsten Gillibrand (D-NY) and Rand Paul (R-KY) could languish while Congress leapfrogs its way to embracing legalization (or at least getting out of its way).

"All the attention will be on legalization," Kampia said, "and there's not a lot of tax revenue for the federal government with just medical marijuana, but if you're talking about the whole ball of wax, with substantial tax revenues, Congress might be inclined to go for the whole enchilada."

The MPP leader wasn't the only one in the room sounding upbeat that day. Drug Policy Alliance national affairs director Bill Piper said that when it comes to marijuana legalization, the train has already left the station.

"I'm very optimistic," Piper said. "The toothpaste is out of the tube. Even Chris Christie can't stop marijuana legalization. Once these initiatives pass in 2016, there's no way back."

The conventional wisdom among drug reformers used to be that we might see federal pot prohibition crumble by the middle of the next decade. But given the lack of disaster and the bonanza of tax revenue in legalization states so far, and the likelihood that a handful more will legalize it next year, that timetable is accelerating.