Over the past thirty plus years the U.S. Marines have been devolving into a second army. This has created exactly the kind of redundant capability that is not only far too common within the U.S. armed forces, but also greatly undermines national security by taking the U.S. Marines away from its core historical mission.
Thankfully, that era appears to be closing. The Marines are now moving back to being an elite, mobile, hard-hitting force of amphibious light infantry. In turn they are once again embracing the corresponding mission set in which they historically have excelled.