Brad Whitaker was an American arms dealer with delusions of grandeur headquartered in Tangiers. Although obsessed with anything related to the military, Whitaker actually never served in any army officially. According to General Leonid Pushkin, he was kicked out of West Point for cheating and then served briefly as a mercenary in the Belgian Congo. (Naturally, Whitaker denied all this, citing them as lies spread by his rival arms dealers.)
Whitaker was the mastermind behind the second coming of "Smiert Spionam." His scheme was to sell weapons to the Russians (purportedly for use in Afghanistan), then use the down payment to buy priceless diamonds, then use the diamonds to buy opium from the Mujahadin. He would then turn around and sell the drugs on the streets of New York, making millions. The only problem was General Pushkin. Pushkin was suspicious of Whitaker, and changed his mind about purchasing the weapons from him. This would mean no down payment, which meant no diamonds and no drugs. And no millions to feed Whitaker's greed, also.
To get Pushkin out of the way, Whitaker had his former KGB friends, including Necros, assassinate various British spies and leave notes saying "Smiert Spionam" on the bodies. Then, he had General Georgi Koskov feign defection to the British so that he could feed them false information and pin the blame for the assassinations on Pushkin. Whitaker was counting on the British to take Koskov's advice and terminate Pushkin, thus getting him out of the arms dealer's hair.
But not everything went as planned. Although M and Minister of Defence Sir Frederick Gray bought Koskov's story, James Bond did not. This despite having personally seen his fellow agent 004 get killed by one of Whitaker's assassins, posing as a KGB operative, in Gibraltar. 007 began his own private investigation in the affair and, with the help of his friend in the CIA, Felix Leiter, his search brought him to Afghanistan where he caught Koskov and Necros red-handed in their attempted opium deal.
After ensuring that their operation went to the scrap heap, Bond headed over to Tangiers to arrest Whitaker. Whitaker had other ideas, and attempted to kill Bond with a high-powered machine gun. Ultimately, Whitaker was killed when Bond's exploding key ring caused a bust of the Duke of Wellington to fall onto his head.