This link popped up in a thread over at Metafilter about this:

http://talkleft.com/new_archives/015767.html

Enforcing marijuana prohibition costs taxpayers between $10 billion and $12 billion annually and has led to the arrest of nearly 18 million Americans. Nevertheless, some 94 million Americans acknowledge having used marijuana during their lives. It makes no sense to continue to treat nearly half of all Americans as criminals for their use of a substance that poses no greater - and arguably far fewer - health risks than alcohol or tobacco.
Its hard to disagree.

I know this issue is off topic for this site, but it's something that has been on my mind for quite some time. I'm not sure what can be done to change these laws, but imprisoning non violent drug users does nothing to help society (unless you count the $$ going to lawyers and law enforcement).

I know I would much rather have my tax money going to preventing things like 9/11 then keeping the next door neighbors 19 year old son in jail for 6 months for having a couple onces of weed on him at a traffic stop.