“This means a great deal to us, and there’s quite a lot of emotion in the room for us, so we’ll let the music do it for us,” Peter Garrett, frontperson for “The Oils,” as their fans call them, said before the last encore of the last performance Midnight Oil would give in the States.

“The first time we jumped in one of those big planes with the kangaroo on the tail with a stop in Honolulu on the way we got up to San Fransisco — I think we played a sketchy club to about 400 people; 300 people didn’t know what we were singing about, didn’t have any idea,” Peter added. But at the MGM National Harbor theater Saturday night, in front of a sold-out audience, everyone knew what this band — who started out nearly 50 years ago — was singing about. Singing with an urgency that remains as vital now as it did back then.