By preventing CITIZENS of the U.S. from a freedom that is otherwise allowed, you're creating a subset lower-class citizen that has rights taken away from him for no other reason than the fact that he is under 21. How can it be constitutional to prevent one citizen from doing what another citizen can, without having just cause?
The drinking age should be lowered in California as well as all states in America. It should be lowered to 18 because at that age a person is now an adult. Adults should be able to buy alcohol, plain and simple. If they can vote, smoke and go to war, they should be able to drink.
California follows the federal standard of age 21 to purchase and consume alcohol and the age shouldn't be lowered. Young adults have enough to worry about--they just got a driver's license five years before being allowed to drink. They should become careful drivers first before getting permission to drink. There is a reason why drivers get licenses first and then drink second, because drinking and driving kills people.