Normally, it would not be acceptable for the conditions for use of the bases to be intentionally reinterpreted each time it is convenient for the U.S. military to do so.
If it is revealed through genome sequencing that the rapid spread of omicron in Japan has its origins in the American bases, the Japanese government will need to take responsibility.
For now, the U.S. and China are allied in not wanting to change the economic status quo. But it is a fragile peace, destined to be interrupted by the unstoppable trade currents, growth and capital.