ACCUS stands for the Automobile Competition Committee
for the United States, FIA, Inc. (ACCUS). It holds the "sporting authority" for all FIA events in the United States. It is considered the "Authorite Sporting Nationale" or some such (abbreviated ASN) for the United States (National Sporting Authority)). It in turn delegates the sporting authority to various member clubs, such as USAC, IMSA, SCCA, etc. for different disciplines of racing.
Sporting Authority means the authority to put on FIA racing events. In order to receive an "FIA Sanctioned" stamp of approval, the event needs to be sanctioned by a member club.
Interestingly, ACCUS will not give exclusive "sporting authority" to any one club in the United States for any specific racing discipline (such as CARS has for rally through the Canadian ASN, or the MSA has for racing events in the UK). This is due to anti-competition/anti-monopoly concerns in the United States. The US is literally one of only a few, if not the only country, where the authority to sanction FIA events is not vested in one organization.
Nick Craw headed the SCCA for 17 years, before he was booted and Steve Johnson replaced him. Do some research on the 'net to find out his background.