National Security Threat Assessment Dilemma

Back in my day, the National Security Council, Defense Intelligence Agency, Central Intelligence Agency, and the Joint Staff War Planners, to name the major players, developed the National Threat Assessment on a regular basis. This document defined what national security threats the USA were likely to face in the years to come. This assessment identifies who and what kind of threats our military needs to be capable defending and defeating should a conflict arise. The assessment also calls for the nation's armed forces to be able to manage multiple conflicts worldwide at the same time. Example: War in Europe with Russia and South Korea defense against North Korea. An attack on Israel by Iran and China invading Taiwan. There are way too many possibilities, almost all of which would be difficult to deal with for US military even with allied support and forward based ships and forces.
Today we are in the 16th year of a Neverending War in Iraq, Syria, Afghanistan, and Yemen. We have a ticking time bomb in North Korea. Ukraine is simmering and a great place for Putin to challenge NATO (USA and EU). Putin also has his sights set on taking Estonia, Latvia, and Lithuania back and get back on the Baltic Sea.
China may push the issue on nationalizing wide swaths of the South China Sea or trying to occupy Taiwan.
These possibilities and many, many others are all considered in the formulation of the National Threat Assessment. In years past, our military was expected to handle two major conflicts in two different regions of the world and still be able to defend the homeland. Today our armed forces are no longer manned and equipped to do two conflicts. In fact, we have stretched and worn out our existing forces and equipment maintaining a sustained war fighting effort in the Middle East. Tremendous money and personnel are being spent in sustaining our various special operations forces throughout the region. Special Operations forces are key elements in fighting IS and alQaeda throughout the region.
The money spent over these over 16 years in training, equipping, deploying, maintaining, overhauling and repairing, fueling, feeding, transporting, and rearming. The trained and experienced people and equipment are always critical but no less so than having enough munitions. In conflict, nothing disappears faster than ammo, missiles, rockets, etc.
Below is the US Navy force levels for the period 1938, beginning of WW2, up to end of 1944. Look at how many new ships were built is such a short time, manned with trained crews, armed and equipped to go directly to war.  This was just the building our Navy. The Army and Army Air Force grew explosively at the same time. It was a national effort of astonishing scale and sacrifice by only 133 million Americans. Imagine, of that 133 million men, women and children, 12 million were in uniform.
Could we do it again?
Navy Active Ship Force Levels, 1938-1944

DATE	6/30/38	6/30/39	6/30/40	12/7/41	12/31/42	12/31/43	12/31/44
BATTLESHIPS	15	15	15	17	19	21	23
CARRIERS, FLEET	5	5	6	7	4	19	25
CARRIERS, ESCORT	-	-	-	1	12	35	65
CRUISERS	32	36	37	37	39	48	61
DESTROYERS	112	127	185	171	224	332	367
FRIGATES	-	-	-	-	-	234	376
SUBMARINES	54	58	64	112	133	172	230
MINE WARFARE	27	29	36	135	323	551	614
PATROL	34	20	19	100	515	1050	1183
AMPHIBIOUS	-	-	-	-	121	673	2147
AUXILIARY	101	104	116	210	392	564	993
SURFACE WARSHIPS	159	178	237	225	282	635	827
TOTAL ACTIVE	380	394	478	790	1782	3699	6084