In a top-two world, the two major parties can’t have too many candidates for the most important offices, like governor. Or it can risk splitting the vote into pieces so small in the first-round that it is shut out of the top-two runoff.

That’s gotta be a real concern as at least five strong Democrats make moves to run for governor in 2018. If the Republicans run only two candidates, you could end up with only two Republicans advancing—and a Republican governor.

Which is why top-two creates a rule of two—or three max. You only want two candidates – and definitely no more than three candidates – running for governor in your party.

Which is why those five Democrats are starting so early—they need to claim one of those three spots. Candidates who are late to the game could get the cold shoulder from the party and donors worried about the top two math.

Gavin Newsom’s leap into the race doesn’t look so weird in this context –it looks smart. He’s made so much noise already that he’s got a strong claim to the three spots. John Chiang and Antonio Villaraigosa and Steve Westly are already openly talking about potential candidacies for the same reason.

But here’s the problem. With Newsom taking one spot, there are only two other spots for those three. And if billionaire Tom Steyer wants a spot, it’s a safe bet he’s going to get it. Money talks, and it’s hard to see Democrats who have leaned on Steyer trying to keep him out of the race.

That leaves us with a primary, within the top two, to be one of the anointed Democratic candidates.

So early 2016 is hardly too soon for a June 2018 governor’s race. At this rate, I wouldn’t be surprised to see someone declare soon for 2026.