A mighty war rages upon the Twittersphere.

For years, Taylor Swift and Katy Perry have traded barbs and "Bad Blood" — and maybe a few ex-boyfriends, too.

While Taylor's subtle digs at Perry — reportedly ignited originally over tour back-up dancers, among other things — are well-documented, Katy herself has kept relatively mum about the whole thing, relying heavily on The Art of Subtweets to do the talking.

Today, of course, proved no exception to the Perry Rulebook of War.

Calvin Harris, who is now just another name to add to Tay Tay's long list of exes/Starbucks lovers, was also keeping things (mostly) nice, even as Swift swiftly moved on to Tom Hiddleston (thus "Hiddleswift" was born) until Harris suddenly felt provoked.

"Hurtful to me at this point that her and her team would go so far out of their way to try and make ME look bad at this stage though ," Calvin wrote on Twitter.

"I figure if you're happy in your new relationship you should focus on that instead of trying to tear your ex bf down for something to do. I know you're off tour and you need someone new to try and bury like Katy ETC but I'm not that guy, sorry. I won't allow it."

The 1989 singer-songwriter has yet to respond to any of this (including the #TaylorSwiftIsOverParty happening on Twitter), but battle lines have evidently been drawn. (IN BAD BLOOD.)

Will she shake these two off once and for all? Or will the Prism princess and the EDM aficionado have their own day in the sun?

Who do you feel is in the right? And are you okay, or do you need to talk to someone about all this?

Vote wisely below — the poll ends on July 20.

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