There’s some sort of political debate happening tonight, but let’s skip over the November 2012 business for a minute and cut to the chase. Are you ready for September 2013?

In NYC elections — where, notwithstanding the last five mayoral races, Democrats hold an enormous citywide advantage — most of the real action happens on primary day. While the 2013 mayoral primaries aren’t until next September, it turns out that many New Yorkers will have to take action tomorrow if they want to vote in the Democratic primary, which is widely expected to determine the winner this time around.

According to the Times, New York has “one of the most unforgiving rules in the country when it comes to eligibility for voting in party primaries.”

Only registered Democrats can vote in NYC’s Democratic primary. And if you’re already registered to vote in New York, but not as a Democrat, October 12 is the last day you can switch your party affiliation in time for next year’s primary. (If you’re not yet registered to vote in NYC, you have more time.)

The good news is that it’s easier for New Yorkers to change party ID now that the DMV processes voter registrations online.

Thanks to reader Albert Ahronheim for flagging this deadline.