A pro-union Celtic punk band is not Wisconsin Gov. Scott Walker’s biggest fan, and they made it clear with a hate-filled tweet sent over the weekend.

The band, Dropkick Murphys, was angry at Walker, a Republican, because he came onto stage at Saturday’s Iowa Freedom Summit to the tune of one of their most popular songs, “I’m Shipping Up to Boston.”

@ScottWalker @GovWalker please stop using our music in any way…we literally hate you !!! Love, Dropkick Murphys — Dropkick Murphys (@DropkickMurphys) January 25, 2015

Given that the band has vocally supported labor unions causes and Democratic candidates in the past, it appears that their hatred for Walker stems from the law he signed in 2011 which ended collective bargaining for most public sector employees and required them to pay more for their benefits.

Walker’s bold act was met with nationwide protest — and a recall election the next year — which Dropkick Murphys also participated in.

In the midst of the protests over Walker’s move, the Boston-based band released a pro-union song called “Take ‘Em Down,” which contains the lyrics “Let em know, We gotta take the bastards down, Let them know, We gotta smash ’em to the ground.”

“[We] would like to take a moment to acknowledge the struggles of the working people of Wisconsin and to pledge our support and solidarity by releasing the song ‘Take Em Down’ from our upcoming album,” the band said in a statement at the time. “We think it’s appropriate at the moment and hope you like it… The Dropkick Murphys Stand With Wisconsin!!!!!”

This is not the first time Dropkick Murphys has bristled at the use of “I’m Shipping Up to Boston” by a Wisconsin Republican. They posted a message on Facebook in 2012 after state Rep. Jeff Fitzgerald used the tune during his intro. (RELATED: Scott Walker In Iowa: ‘Go Big And Bold’)

“We just got word that Wisconsin State Rep and Speaker of the State Assembly Jeff Fitzgerald used ‘Shipping Up To Boston’ as his walk-on song yesterday at the Wisconsin GOP Convention in Green Bay,” the band wrote. “The stupidity and irony of this is laughable. A Wisconsin Republican U.S. Senate candidate – and crony of anti-Union Governor Scott Walker – using a Dropkick Murphys song as an intro is like a white supremacist coming out to gangsta rap!”

Walker did not respond to the band’s tweet.

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