Government databases are currently estimated to be 1/3 crap. Seriously. Even the big commercial database companies have issues with data integrity. What rights would citizens have to assure that any information regarding them in this database is correct?
If your idea of constitutional government is one that ensures optimum law enforcement, why not just chip everyone with GPS chips. That way you could 'prove your innocence' just like with this DNA database.
The only reason we need government is to secure the individual rights of its citizens. The Founding Fathers understood as much -- see the Declaration of Independence. If I thought that DNA databases ran counter to this basic fundamental principle, I would not be here arguing for them.
I do agree with the middle sentence, but would add that we need government (including law enforcement) in order to secure the rights that we already have as human beings.