Stir all the ingredients with ice in a mixing glass. Strain into a chilled martini glass. Garnish with the olive.
Franklin D. Roosevelt was the first to popularize this odd drink. After working behind bars, I don't think many bartenders would drink the Dirty Martini — the brine in the olive jar can get pretty funky after sitting around for a while. If you want to try this one at home, get a jar of gourmet martini olives like the Tipsy Olives sold by Sable and Rosenfeld, which are packed in vermouth and spirit vinegar. Another idea is to remove half of the brine from regular store-bought olives and refill the jar with dry vermouth. If the drink is made on the rocks, stir in the glass.