Round 1 (Brando vs Washington)

This is another tough round, with 2 amazing actors and badasses going head to head. They both are oscar winners and multiple nominees. They both have long stretching careers. So lets evaluate the badassery.
Brando has the godfather as his oscar winning turn vs Washington in Training Day, and honestly only the Godfather could beat Denzel in Training Day. Denzel plays a cop so corrupt he makes his rookie partner smoke PCP under the guise of it being marijuana. He shoots a drug lord and makes it look like self defense. He fathered a child with Eva Mendes. But the Godfather is still the Godfather.
Denzel has Malcolm X, which is the guy who was the most badass civil right leader ever. So points there. Brando has On the Waterfront, which shows how badass a guy can be even as his life descends.
Denzel wins, and for one reason. These 2 guys have had great careers, but Denzel is still a badass today, look at Inside Man or Man on Fire. Brando truly faded away after the Last Tango in Paris, and his character in that was more disturbing than badass. Brando has better films, but his lack of relevance at the end of his career makes him less badass.