Which should come first when writing a song?

by Josh Clouse
(Kentucky)

During writing a song you need a beat, would making the drum track first make it easier before doing the guitars? I thought of this after I watched the deluxe edition of the "Between the Buried And Me" with their new album "The Great Misdirect" . They said that first they got the drum tracks done for every song in like two days. Then then went to the guitars. This just makes me curious.I have written songs. But I just want to know if having the whole drum track finished then moving to the guitar will make everything more simple, sense you already have a beat made.