The budget is the responsibility of Congress, but if the President got on TV during the SotU address and said "Mr. and Mrs. America, your sons and daughters are using out of date equipment, can't get supplies or ammunition, and are running out of fuel while on missions. Their lives are in danger because Congress won't allocate the money for basic funding," the phones would be lit up in every Congresscritter's office before he said "Good night and God Bless America."
tl;dr Both sides are at fault.