Some PDs would hire you at some point, but the DEA would not. Below is from the DEA's website.
Applicants who are found, through investigation or personal admission, to have experimented with or used narcotics or dangerous drugs, except those medically prescribed, will not be considered for employment with DEA. Exceptions to this policy may be made for applicants who admit to limited youthful and experimental use of marijuana. Such applicants may be considered for employment if there is no evidence of regular, confirmed usage and the full-field background investigation and results of the other steps in the process are otherwise favorable. Compliance with this policy is an essential requirement of the position.