By SCHUYLER DIXON
AP Pro Football Writer
ARLINGTON, Texas (AP) — Dak Prescott threw four touchdown passes, DeMarcus Lawrence returned an interception for a score and the Dallas Cowboys routed Washington 56-14. The Cowboys had already clinched the NFC East title with a Las Vegas win over Denver about an hour before kickoff. Dallas tied the franchise record for most points in a first half while taking a 42-7 lead. Washington was frustrated to the point that defensive tackles Jonathan Allen and Daron Payne scuffled on the sideline.