18th and 21st Amendments: Questions

Based on the lesson of Prohibition, what should we be doing about recreational drugs?
If Prohibition were enacted today, what other substances, devices, or anything else might be made illegal?
What would have happened had the 21st Amendment never been enacted?
Was alcohol use a serious enough matter to warrant a Constitutional Amendment? You could argue that meth is more dangerous than beer; do we need an Amendment to prohibit it?