So, then the president has no obligation for border security, quelling riots or even balancing the budget.. Not in the constitution either
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to provide for the common defense... is right there in the preamble.
If we went by the Constitution, (Original Intent), the Federal Government would do much less, and balancing the budget would be far easier. Damaging the full faith and credit of the United States by letting a banking cartel manage our money supply isn't exactly in the Constitution. Take that up with the Jekyl Island Crowd who pass out the promissory notes we call "money".
As for quelling riots, the military is constrained by the Posse Comitatus act, even with the NDAA powers.
Quelling riots is first and foremost the responsibility of local and State Governments, and they can call upon the Federal Government for assistance, but have universally FAILED to do so, and abdicated their responsibilities within their own jurisdictions. Short of a 'regime change' within those jurisdictions, the riots will continue, unless the people take matters into their own hands or the Mayors and Governors decide to finally get the situation under control.