It depends on the offense and the maximum punishment; generally speaking misdemeanors are crimes in which you could be incarcerated for 1 year or less; felonies more than 1 year.
It's hard to say exactly. Each state may have it's own definition so you should seek an attorney licensed in each state to be sure. It may be that since a special court-martial normally contains charges under Titles 10 and 18 of the United States Code and that they would look to a federal definition.
Generally, the federal courts will look at it like this, if the maximum term of imprisonment authorized is:
(1) life imprisonment, or if the maximum penalty is death, as a Class A felony;
(2) twenty-five years or more, as a Class B felony;
(3) less than twenty-five years but ten or more years, as a Class C felony;
(4) less than ten years but five or more years, as a Class D felony;
(5) less than five years but more than one year, as a Class E felony;
(6) one year or less but more than six months, as a Class A misdemeanor;
(7) six months or less but more than thirty days, as a Class B misdemeanor;
(8) thirty days or less but more than five days, as a Class C misdemeanor; or
(9) five days or less, or if no imprisonment is authorized, as an infraction.
These are all discussed at 18 USC 3559.
My two colleagues are right on point. It depends on what you are facing at SPCM. Your TDS attorney/office can tell you precisely effects of this conviction.
My answers are not intended as anything more than an educational response to generic questions posted on this site.
Ordinarily, a special court martial would be of the level misdemeanor. For drug offenses, the quantity of the drug will control. You need to contact a JAGC civilian attorney with your court documents and Page 9 for page a better recommendation/opinion.