How can I become a police officer after spending my college years smoking marijuana?

I have always been interested in being a police officer. Unfortunately, for the last 4-5 years I have continuously smoked marijuana. Obviously, this recreational drug use is not conducive to a career in law enforcement. Recently, I have made the choice to stop wasting my time partaking in this idiotic pursuit, and I have decided I would like to realize my ambition of becoming a police officer. Besides this frequent use of illegal narcotics, I have never been arrested and have lived a fairly upstanding life. I am a very gifted individual, both mentally and physically. I know that If given the chance I would be able to perform this job at the highest ability. I would like to know what the steps are to distance myself from my past transgressions and begin to proceed with a career in law enforcement. Thank you for your time and consideration on my inquiry.