Have you learned/read of any of the permittees in the Gulf, taking immediate steps against the US Gov't?
They can't. Their permission to drill has been withdrawn as is the right of the USA government. This is also basically the same rights as the Belize government has on all of the Production Sharing Agreements.
The Belize Government can pull the plug at any time it chooses, and if the company tries to sue they will be shooting themselves in the foot. If they struck anything after successfully suing the government, the the government would not give them their annual renewal of their PSA's nor would they give them a production licence.