Can you be turned down from the Marine Corp if you have graduated from the Citadel? (Like for a minor medical issue you were born with)
You mean the South Carolina military school of that name? I expect you could be turned down, yes. I’d be suprised if the USMC had outsourced its recruitment/selection programme to other agencies. It might be unlikely that you would be turned down, but the decision to accept you into the USMC is made by the USMC, not by a public univesity.
The Citadel is one of six senior military colleges, recognized under federal law, whose graduates are guaranteed commissions in the armed forces upon graduation. (Unlike graduates of the service academies, however, graduates of the SMC’s don’t have to seek commissions if they don’t want to.)
Of course note the qualification about being “medically and physically qualified for active duty”–you could conceivably be turned down as unqualified. I have no idea how often (if ever) this occurs.
Also I’m not sure why the duty of “ensuring” commissions is entrusted to the Secretary of the Army, since SMC graduates presumably serve in all four military branches. Perhaps some veterans can shed light on this.
They don’t. Military = Army in this context. (As in the United States Military Academy, better known as West Point, which trains army officers.)
AFAIK the only service academy that trains Marine Corps officers is the US Naval Academy at Annapolis. But I might be wrong about that.
Title edited to indicate subject. Please use descriptive thread titles.
Colibri
General Questions Moderator
According to wiki
According to that page I’m wrong about Citadel graduates only receiving commissions in the Army.
That’s correct you were wrong. 
The Citadel does require a physical before being accepted as a student. I’m 90% sure that you still have to take a standard pre-commissioning physical after you accept your commission. A lot can happen in 4 years and your pre-freshman physical won’t count at that point.
So to answer the OP if you had a physical problem that would keep you out of the military it will keep you out of the Citadel. You can also get a medical problem which will later keep you from commissioning.
Missed edit.
Some informed speculation: There are some tasks that are common across the military and one branch is sometimes designated the “lead agent” for that. Most likely, being the largest branch, the Army runs military entrance medical screening for all services. Each servcice can still apply different criteria to those tests - ie the marines won’t take someone the air force would.
Another “lead agent” example is buying HMMVs. When the Marines need one they work thru the same program manager as the Army, not directly to the manufacturer.
All students (with a few exceptions like returning veterans) must be in ROTC. That school (and I believe all SMS) have Army ROTC. It’s as simple as that. And they all are traditionally schools which produced army officers from before there were such regulations and before there was ROTC.
But The Citadel also has Naval ROTC.
I went to and graduated from one of the six senior military colleges.
Did over 3 years of Army ROTC then in December of my senior year the Air Force came in and said they would accept all Army ROTC credits. Myself and about 50 others took up the offer. Took the flight physical and there was a benign abnormality in the EKG. That was it. I was no longer eligible for any branch of the service and booted out.