Yes, I've said for years that the "war on drugs" is the biggest current exception to the general trend of increasing personal/civil liberties in America. Note that I classify regulation of recreational psychotropics as an infringement on personal/civil liberty, but I classify regulation of medicines/remedies as an infringement on economic liberty. The (imperfect) distinction is between protecting you from your vices versus protecting you from your ignorance.
Wikipedia tells us there was indeed involuntary militia service in America as early as the Revolutionary War. The scale of conscription has of course been dominated more by the scale of warfare than by the general trend in civil liberties. Military conscription in America has been effectively dead for decades, and modern warfare makes it obsolete for a superpower like America.
I classify taxation as an infringement on economic liberty, and so the trend in taxation in fact supports my thesis. For more details, see http://knowinghumans.net/2006/07/fear-neophobia-not-police-state.html.