Most of what I'm going to say has been said before in this thread:
Getting high isn't going to effect change. If ten times as many people got high on psychedelics, it probably wouldn't effect change.
Why? I see the (regular) drug-using community as a largely manufactured one, one that is a by-product of the anti-drug laws we have in place. It is defined by those laws, and cuts across social classes and races, but there is no coherent program for them to latch on, nor any interest in finding one.
For example, take white-collar regular drug-users, the Wall Street movers and shakers who can shell out cash for H and coke like it's nothing. They are, it seems, very rarely punished or caught for their "crimes", compared to your lower or middle-class users. However, they simply have no common cause with those users. They almost certainly don't sympathize with self-professed psychonauts, or stereotypical "crack-heads" and tweakers, or ravers, whether those others are apologists for drug use or not. They're probably from different classes, and see things from totally different perspectives; they have their own interests, and the biases they were inculcated with, and the political clout to resist change. In short, your average wealthy white coke user is probably no more inclined to legalize weed or LSD than a middle class straight-edger. Likewise, the members of these lower demographics probably have equally little shared ground with the upper.
Even among the lower demographics, there is difference in causes--how many people do we know who are weed smokestacks who are still against the legalization of H, ecstasy, or LSD? Psychonauts probably feel that they have little common cause with those "childish E-tards", while "E-tards" feel like they have little common cause with "crack heads", and so on and so on. Of course, there's also the racial and class biases among this lower demographic, but perhaps we should leave that be for now.
As I said before, drug-users are--or seem to me--to be a manufactured class/subculture. As such, they have little or no connection to the powers that run this country. Most of those hippies and psychedelics proponents in the '60s and '70s probably did NOT become politicians at all, and the ones who did *had* to tailor their politics to get the same office from which they could also effect change! In short, one has to join "the Man" to change him, but to change him one has to pander to the same voters who support "the Man". If Bush (in some bizarro alternate universe) decided to legalize drugs tomorrow, he'd be impeached in no time. If the congress tried to legalize drugs, the president would veto it, or the states would reject it individually. If the states tried to legalize drugs, the counties, cities, and parishes could reject it, and so on. The government is its own buffer. This whole scenario doesn't include the fact that fewer and fewer people vote these days--and mostly the ones from the vaunted younger demographic who are supposed to be the vanguards of change.
*If* any change is going to happen to U.S. drug policy, it will be from the grassroots level, and it will probably also be extremely slow, probably taking many generations. I doubt any of us on the board today will live to see it, realistically, though of course I hope I'm wrong.