Final answer:
Commanders may direct drug testing under conditions such as random testing without prior cause, with reasonable suspicion, or after a member has completed rehabilitation. Public holidays are not a standard condition for drug testing.
Step-by-step explanation:
Commanders can direct drug testing under a few specified conditions according to military regulations and policies. These conditions include random testing without prior cause or reasonable suspicion to deter drug use within the ranks. Commanders may also order drug testing when there is reasonable suspicion that a member is using illegal drugs. This suspicion must be based on specific, credible information. Additionally, drug testing is often mandated for individuals after they have completed a drug rehabilitation program, to ensure they remain drug-free. Drug testing during public holidays is not a typical condition mentioned in standard regulations regarding drug testing. The specifics of when and how drug testing can be conducted may be governed by military guidelines or policies, and the rights of individuals in such circumstances are subject to legal interpretation about due process and privacy rights.