This probably seemed like a good idea at the time. Four years later, Elvis had OD'd on barbiturates twice, gotten divorced from his wife and gained a cartoonish amount of weight. And Watergate had pushed Nixon from the White House. In retrospect, not the best do-gooder pairing.
The meeting was, as a symbol, about a lot more than drugs. It was about a man who used to get censored on national television for his scandalous hips joining forces with the face of hard-line conservatism. Fortunately, kids around the world were moving on to new heroes who weren't afraid to make a bad decision or two, and more people are making rock and roll today than ever before.