I've been representing defendants in drug cases (and in criminal cases generally, from disorderly conduct to homicide) for more than 35 years.
During those years, the criminal justice system has become a huge industry, with more and more people arrested, charged, and incarcerated, often for things that the police would have overlooked as trivial when I started law practice. Sadly, drug arrests are a primary way that police officers get promoted. In general, drug cases are easier to prove and prosecute than more property or violent crimes. In my opinion, society would be much better off if the system would treat possessory drug offenses as health problems rather than crimes.
The job of a criminal defense lawyer is to shepherd the client through a bad system with as little damage as possible: if dismissal or aquittal aren't realistic, then with as lenient a sanction as can be achieved. Doing this well requires compassion, commitment, intellectual creativity and rigor, and an unflagging devotion to the values set forth in the Bill of Rights.
Before law school, I was involved in the civil rights and anti-war movements of the 1960's, and these experiences still shape the kind of person and lawyer that I strive to be.