Legal Question in Military Law in Massachusetts

This sounds more like venting than a legal question, however: The United States Supreme Court has long ruled that the constitutional power of Congress to "raise and support armies" allows for the establishment of recruitment standards consistent with recruiting and building a disciplined force, even if such standards are discriminatory (physical requirements) or objectionable to others (former prohibitions based on sexual orientation). The same Constitution grants that the President shall be Commander in Chief of the Army and Navy of the United States, and of the Militia of the several States, when called into the actual Service of the United States.

On the issue of recruiting: while Massachusetts has decriminalized possession of 1 ounce or less of marijuana (and only possession, not use/smoking), generally speaking this is irrelevant; both federal law and regulations classify marijuana as a controlled substance and criminalize its possession. The Army is (ultimately) a federal institution. All military organizations count payment of a fine as a "conviction" for recruiting purposes, just like a CWOF (continuance without a finding) counts as a "conviction" for recruiting purposes.

Recruiting standards fluctuate based on the needs of the respective services. Right now, confirmed prior drug use is a disqualifier, as a re a collection of other criminal offenses. If there was a shortage of personnel, entrance requirements might be altered to create a larger pool of applicants, or waivers might be made available. General requirements can also be waived based upon special circumstances (for example if you were fluent in certain languages or had highly specialized skills that were in demand)... this is essentially an employer making a risk-benefit determination. Right now, the Army has plenty of people applying for every position it has vacant, and is expecting a reduction in authorized numbers based on upcoming budget issues and the end of major operations in Iraq.

If serving in the Army is your ultimate goal, there are things that you can do to further that plan and make yourself more attractive to that employer, possibly under the Great Skills Program (google it and talk to your recruiter). You can also re-apply and check on changes in available waivers... or pursue a career in politics.