The U.S. and its NATO allies have been fighting the Taliban in Afghanistan since soon after the 9/11 terrorist attacks on New York and Washington in 2001, though the mission officially changed to training the Afghan army and police a few years ago. On Monday, Defense Secretary James Mattis made an unannounced visit to Afghanistan to assess the situation as President Trump decides whether to send more troops to help quash a resurgent Taliban. Mattis and the top U.S. commander in Afghanistan, Gen. John Nicholson, strongly suggested that Russia is behind a flood of arms to the Taliban.
The U.S. will have to "confront Russia" over "denying the sovereignty of other countries," including Afghanistan, Mattis said at a news conference in Kabul on Monday. "For example, any weapons being funneled here from a foreign country would be a violation of international law." When asked if he wanted to refute reports that Russia is arming the Taliban, Nicholson said, "Oh no, I'm not refuting that," adding that the U.S. has continued to receive such reports of Russian assistance to the Islamist insurgents.
After the Soviet Union invaded Afghanistan in 1979, the U.S. covertly supplied arms to the Afghan mujahideen resistance, which eventually caused enough loss of Russian blood and treasure that Soviet Russia pulled out in 1988. The loss in Afghanistan has been credited as a significant cause of the Soviet Union's fall in 1991.