The President commands the military, negotiates treaties, nominates various officials for confirmation. Probably the most leeway relates to being called to ensu

The President commands the military, negotiates treaties, nominates various officials for confirmation. Probably the most leeway relates to being called to ensure laws are faithfully executed. So it seems reasonable the Executive can police independent agencies to ensure they operate as authorized by law, but I don't see how that challenges the establishment or existence of lawful independent agencies. NSF is one thing but say an independent agency that does things like negotiate treaties or command the military or nominate Supreme Court justices should be off the table (But on the other hand, theoretically the Executive should be able to voluntarily authorize legislation that enables those things if they wanted to. Just saying I can see cooperation possible but a veto override probably won't work to force it on an unwilling Executive).