Federal government is supposed to have limitations to what they can restrict states to do, as long as a states is not mistreating population the federal government is supposed to stay out of their business. Much like how the EU stays out of individual countries business. The EU is more like the United States of Europe, think of that analogy when you think of American governance.
The federal government are aliens, they are a few men in seats half way across the country that make decisions about how I should live my life, yes they do things more often than not in my favor positively, but very many times they act in ways that are very negative. They are very short sided in some of there actions.
The original clause I speak of was meant to boost trade during the great depression, it has been proven now that restricting the sale of foreign goods in America actually prolonged the depression another 6-8 years. It is an abomination, and I have no way as a citizen to challenge this law in the book. Later on the clause was used to restrict the sale of drugs, which Nixon used because he was scared the counter culture would spread across America.
I understand why Nixon did this, even Hunter S Thomas the famous hippy journalist noticed the counter culture created a generation of dead beats, degenerates and so on. He acted hastily to the drug problem in the united states, instead of trying to regulate it like what he should had done he created a all out drug war which is a failure which we throw millions to each year. If he had regulated marijuana, and eliminated the black market, we wouldn't be in this mess now.