The team is looking to 'defend' its national title. [=to win the national title again]
As a U.S. senator, it is my responsibility to 'defend' [='uphold'] the Constitution.
She successfully 'defended' her championship. [=she won the championship again]
(..) - I want you to tie up for hours. Stall their deliveries, push them off the streets! Bury them for hours, give me time! You defend the machine. Hit this guy! The usual thing, criminal, blocking a relief bill, - - starving the people. Joe, will you get back into that Senate! (..)1939 Mr. Smith Goes to Washington