The 1919 constitutional amendment that outlawed the sale and consumption of alcoholic beverages in the united states failed because

It was seen as ok, to break the law.  
The country did not have enough people trying to enforce the law.  
People would make alcohol, or go find it on the corner.  

Many people just ignored the law and did it anyways. They did not have enough police force to stop this. Another main reason is because the government lost a lot of money due to the lack of TARIFFS

Slower

Ibelieve it is