Issue:

US legislature has near unlimited power over any US based organisation, especially when it can see as carrying out an important public function. It is entirely possible in the future for US legislature to make new laws which specifically target ICANN and its functions, or may generally target them under a class of organisations or functions. This can completely throw out of gear ICANN's global governance function and its primary accountability to the global community.

Solution:

Evidently, there can be no other solution for this issue than to grant ICANN one time general immunity under the US International Organisations Immunities Act, with proper customisation and exceptions for ICANN to enable to be able to perform its organisational activities from within the US. The chief exception I understand would be the application of California non profit law.