If we wait for an agreement that will actual work, this war will still be going on in 100 years. As it is, the only way we are getting out of the war is when the U.S. goes bankrupt.
Does that sound familiar? That is what happened to the U.S.S.R. when they tried this in Afghanistan.
At least he tried and there was an agreement in place.
Regardless, Rand has been calling for troops to come from Afghanistan and various other places since he got to the senate in 2010.