Simon Denyer tries to make sense of the Trump administration’s South China Sea position. Notably, there is no legal basis for blocking Chinese access there:

Mira Rapp-Hooper, a South China Sea expert at the Center for a New American Security, called the threats to bar China’s access in the South China Sea “incredible” and told Reuters it had no basis in international law. “A blockade — which is what would be required to actually bar access — is an act of war,” she added.

If that is what Trump administration officials have in mind, it would be a colossalerror, and it would probably receive little support from our regional allies. The conceit that such a blockade would be imposed in the name of preserving freedom of navigation makes it seem even more ridiculous. Because it would challenge China’s access to territories that it considers to be its own, it guarantees that they would refuse to yield to our attempt at coercion, not least because they would see this as a question of sovereignty. If this really is the administration’s position, Trump continues to think that China can be forced to make a deal on things that it considers to be non-negotiable, and that is bound to lead to costly failure. It also bears repeating that the U.S. won’t benefit from doing any of this, but would pay a substantial price from armed conflict with another major power while suffering the economic effects of the disruption to trade. Trump claimed in his inaugural address that he was going to put America first, but picking a fight with China on its doorstep over something that matters far more to them than it matters to us does just the opposite.