Well since this didn't get moved to the musician's side, I will leave out the technical mumbo jumbo....

If you listen to this song while trying to find "home" you can figure it out pretty quickly. The melody of the guitars and vocals both beg for the song to resolve to E major. After you doodle around a bit you can pretty quickly tell "home" is E. 

The intro and lyrics guide you...."this is love that we've been working on". That's your resolve. "We pulled to many false alarms". Is also the resolve. 

when John's singing over the C#m, it's setting up the resolve melody. Same with the guitar melodies, they're setups to the E chord. 

Brandon