The successful marijuana initiatives earlier this year may have started something.
Here's a look at the impact a new documentary - The House I Live In - is having on attitudes about laws that treat non-violent drug criminals like violent criminals and send some to jail for life sentences for what seem like relatively minor offenses. It has led to the development of a caste system in the US since those convicted are burdened with a criminal record. The conspiratorially minded think that's the point.
But when opinion leaders like Pat Robertson think we should decriminalize marijuana, things have changed. Majorities of Americans now favor legalization (not that that always matters). The media is more likely to publish editorials favoring legalization as well.
As of yet, this only applies to marijuana, not harder drugs.
One sticking point mentioned in the story is the financial benefits that certain people and institutions receive from the status-quo. Drug laws give law enforcement something to do. And the rise of privately owned prisons means that the incarceration of large numbers of people - for whatever reason - produces profits. I would guess that policy shifts will not really occur until powerful interests see more money to be made when marijuana is legal rather than illegal. Tobacco companies are apparently ready to go producing marijuana cigarettes (will we still call them joints? Doesn't seem appropriate.). They have tremendous political pull.