The organization designated as the Joint Chiefs of Staff (JCS) was officially established in 1947, but in practical terms it originated in 1942 when four-star flag officers from the Army and Navy began meeting to facilitate improved coordination between the Navy and the War Department. It was not until 1986, however, that the office of Vice Chairman was established to assist the Chairman in the execution of his duties, including presiding over meetings if the Chair is absent.
By statute, the Vice Chairman of the JCS (VCJCS for short) may not come from the same branch as the Chairman (although the President has the authority to temporarily waive this restriction during transitional periods in both offices). Vice Chairmen are appointed to two-year terms, but may serve only a total of three of during peacetime (the number of reappointments is unlimited “time of war.”) While the office of VCJCS is outranked only by the Chairman, it does not carry any authority for military command over any of the Armed Forces, including the various Chiefs of Staff.
It’s sometimes assumed that the VCJCS may perform duties prescribed by the President, but statute makes it clear that his functions are limited to those held as a member of the Joint Chief of Staff and what is prescribed by the Chairman (assuming the Chairman’s orders have the approval of the Secretary of Defense).
The insignia for the aide to the Vice Chairman of the Joint Chiefs of Staff features a shield whose design is highly similar to the office’s positional flag office—the only significant difference is that two of the four stars on the shield are placed on the middle blue stripe, while on the flag the stars appear only on the white stripes.