What is the difference between a Specialist and a Corporal in the Army? Inquiring Marine minds want to know.

To me it is simple. A Specialist (E-4) Specialized in a certain area now there was some disagreement as to where this rank specification should be used. Combat Arms Units Corporal, E-4; other units not combat arms specified Specialist (E-4). This was somewhat a debate a few years ago.

Kinda like leavin the Union that repesents the Spec4's. to become low level management. ( chuckle, gotta love the Spc4 Mafia.

The Corporal rank is meant to recognize a soldier who has been placed into a leadership position, and seperates the shammers from the leaders among the E-4 pool. You will find Corporal's mostly in an MOS that is difficult to promote to Sergeant due to high points requirements and a a large pool of competing candidates.

More responsibility and/or in a leadership position. I was a Spec 4 while in the Batt S3 but when I was needed to run the schools NCO position, I was laterally promoted to CPL as per my S3 Maj and E7.

A corporal is considered a NCO meaning they have more responsibility. They also have to go to all the NCO meetings withing the unit. A Specialist isn't and doesn't. Depending on the unit you could get laterally promoted if you have been you the board/WLC and are waiting on points.
I only saw Corporals in combat arms units though.

Almost all MOS's have Specialists at the E-4 rank, it is actually the normal progression in the Army. CPL isn't a promotion at all, it is a lateral appointment (I believe it must be approved by a BN Commander). Part of the qualifying factor is that you need to have at least two direct reports and of course are an E-4 already or being promoted to one. SPC is not considered an NCO, but a CPL is. Same pay and benefits though. The only high point is that you may garner more commanders points or get extra weight for the E-5 Board, not a lot of incentive going on there. This was accurate as of 1995 at least.
Oh yeah, Is PT now optional for NCO's? I saw someone state that in this feed, it certainly wasn't when I was in. Just curious.

You need to make Corporal 1st are you will never move up the Sgt. ranks. A Spc. cannot move to Sgt.

A specialist 4 isn't a leadership roll and a Corporal is. I was an acting Corporal for about 8 months in 1982. I was supposed to go to the E-5 board while in Panama, but since I already had orders to transfer, I didn't get to. My squad leader put me in for hard stripe Corporal. Being a Corporal put me ahead of others that were a specialist 4.

Besides same rank, (E-4), a Corporal is NCO, and depending on MOS, Corporal holds higher authority.
There are other things also.

Corporal is aNCO ,a specialist is not