Ezra Koenig has been far from quiet politically. He’s come out in support of Bernie Sanders, spoken about the presidential candidate on CNN, and performed at Sanders rallies in Iowa City and NYC. Now he’s set his sights on a New York voting policy that he believes to be “garbage.”

New York is one of 11 states with closed primary elections. This means only voters who are registered as either Republicans or Democrats are allowed to vote. NY is also the only state in which currently registered voters must declare their party affiliation more than six months prior to the primary in order to vote. As The Guardian explains, the New York State Board Of Elections’ deadline for registered voters to change their party affiliation ahead of the 2016 presidential primary was 10/9 of last year. First time voters were able to register for the primary up until 3/25, but that deadline has also passed.

Because of these rules, any New Yorker who isn’t currently registered as a Republican or Democrat has no way to vote in tomorrow’s primary. As of this month, that group includes 2.9 million of New York’s 10.7 million active voters, and Koenig is pissed about it. The Vampire Weekend frontman took to Twitter to air out his frustrations, and even tweeted directly at NYC Mayor Bill de Blasio with some choice words. Check out his tweetstorm below.

The New York primary is bullshit. Whoever wins – this is garbage. It's voter suppression. pic.twitter.com/M4hVyDljaG

— Ezra Koenig (@arzE) April 18, 2016

.@BilldeBlasio you're the only elected NY democrat I've ever met (shoutout to steve buscemi.) plz speak on this or we're enemies now

— Ezra Koenig (@arzE) April 18, 2016

.@BilldeBlasio i don't wanna fast-track u to the number one spot on my enemies list BUT YOU'RE OUR MAYOR. FUK THIS

— Ezra Koenig (@arzE) April 18, 2016

first time voters could register as democrats in march. unaffiliated voters had to do it in october. https://t.co/N9dSNUbKaW

— Ezra Koenig (@arzE) April 18, 2016