Several months may be needed to clear the network of caves and tunnels dug in Afghanistan's eastern mountains of remaining Taliban and al Qaeda forces and cut off re-supply routes from Pakistan, U.S. and Pakistani military officials told Sens. Carl Levin (D-MI) and John Warner (R-VA) last week. Levin and Warner -- the Senate Armed Services Committee chairman and ranking member, respectively -- spent last week visiting with U.S. military forces and diplomats in Uzbekistan, Pakistan, Oman, Bosnia, Hungary and...