Star spangled banger lyrics panic at the disco

I think you might be thinking of the song "I Write Sins Not Tragedies" by Panic! At The Disco, not "Star Spangled Banger". The lyrics to "I Write Sins Not Tragedies" are:

"Once upon a time, a few mistakes ago I was falling for you Once upon a time, a few mistakes ago I was falling for you

I write sins not tragedies I write sins not tragedies I write sins not tragedies I write sins not tragedies"

But if you're looking for a song with a similar title, Panic! At The Disco does have a song called "Star Spangled Banner" which is an instrumental track that's a cover of the US national anthem. It's not a song with lyrics, but rather an instrumental arrangement.

If you're thinking of a different song, please let me know and I can try to help you identify the lyrics!