I'd have to say Reagan, because when Bin Laden and his muhajadeen were fighting the Russians, Reagan supplied them with lots of weapons.
I disagree there. The Afghan Mujaheddin were not terrorists, at least not in the traditional use of the word
He did however fund Saddam Hussien, Jonas Savimbi of UNITA, the Contras, and Eritrean Liberation Front (been a populist dictatorship worse than North Korea since 1991). He also launched the invasion of Grenada when the Cuban backed PRG overthrew the government there.
Later, those same weapons were used against us.
Not really.
The warlords that fought for the Muhajadeen generally had no association with the Taliban, and those weapons continued to be used to fight the DRA and Taliban after the US stopped financing (assuming they did). I guarantee you that some were used during the invasion of Afghanistan by the Northern Alliance in 2001.
Wish they were used by the Taliban though. It would of been nice if some more US conquistadors died during the course of the occupation.