In August 1996 Bin Laden declared war on America from his Afghan cave, citing the fact that U.S. forces were still in the Persian Gulf.
His father's pitch to the incoming mujahideen was different, focused on Arab discontent over the Israeli-Palestinian conflict, an issue with broader appeal. They came in droves, a new generation of men seeking jihad, or holy war, against the infidels of the West.
Omar describes how during meetings of mujahideen in Kandahar, leaders would play videos of perceived Israeli atrocities, the demolition of homes and the killing of civilians. Men would leave the meeting raging to fight. Between Israel and America, Osama saw America as an easier target.
"He thinks America is weaker than Israel. America is easier to get attacked, with its huge cities," Omar said. "He sees America is the main power, but in fact is weak in certain ways."
Omar believes most Al Qaeda fighters can be turned, and that efforts like terrorist rehabilitation programs in Saudi Arabia do work. The problem, as he sees it, is that their home countries are reluctant to take them back.
"The jihadis, as I know them, want to return to their country and they're afraid because they know they are going to be killed or poisoned or imprisoned, so they stay with my father," he said.
When Omar broke with his father and left Afghanistan before the Sept. 11 attacks, he sought to reclaim a life he never had. His family is trying to get access their inherited Bin Laden wealth, but Omar says the money is "stuck," held by governments in Sudan and Saudi Arabia.
Omar says his dream in life is to reunite his family and succeed as a businessman. Being the son of Osama has made both a challenge, and left him expressing a deep discomfort.
"I am a peaceful man, but I don't have peace," he said.