The US Military is the number one user of Oil in the US. If the Military would cut back its use by 90% (what German non-armored non-airplane units had to do from 1942 onward) could it still defend the US? It be hard, but doable. The savings in fuel usage may even make the US self sufficient in oil (If you consider Canadian and Mexican Oil "domestic" which in a pinch can be viewed as such given how close all three economies are to each other).
The problem is the US Military does NOT want to defend the US, it wants to be able to win what ever war the US gets into, no matter where. That requires the ability to project power and that requires a lot of access to oil That ability cost MONEY in addition to OIL.
Thus the issue is how can we "pay" for the US Military? Do we raise taxes? or do we cut back domestic spending so that Grandma has to starve to death so that we have money to project US military power? No one wants to raise taxes, so the choice is Grandma being able to feed herself or the ability to project power. Which do you prefer? I prefer Grandma eating which means cutting back the military given NO ONE WANTS TO RAISE TAXES ON THE 1% (and that is where the money is thus where we have to raise taxes).
FDR had a 90% tax rate on the 1% (subject to a 50% long term capital gain rule, thus if the investment lead to income five years later, 50% of any gain was NOT taxable, but 50% of the gain was taxed at 90%, in effective a 45% tax rate on long term gains, but a 90% tax rate on any gain do to short term speculation including on the oil and stock markets). Kennedy reduced this to 70%, Reagan to 35% (AND treated long term gains the same as short term speculation gains, thus someone who made an investment in a factory that produced a profit in five years, was treated the same as someone who made a gain speculating on stock, bonds or oil), and Bush jr went to even lower rates.
I do NOT see a return to the 70% tax rate let alone the 90% tax rate. Thus taxes will NOT be raised, thus the choice cutting non-military spending (Social Security is the single biggest non-military item) or the Military? That is the choice, Grandma's dinner or oil for Planes flying over Afghanistan? Which is your choice given the lack of any support for a tax increase?