One example of our considerable vulnerabilities:
Currently the USA gets most of its semiconductors--critical for almost all American electronics and especially war machines and equipment--from Malaysia, Taiwan and China. Malaysia has far more formal ties with China than it does with the USA and if China should go to war with the USA, the first thing it would most likely do is overtake Taiwan or at least make it impossible for Taiwan to help the USA in any way.
That creates a significant security threat to the USA. We should be creating an environment in which the few U.S. companies manufacturing semiconductors would step up production sufficient to sustain us should that be necessary. That would be Intel, Nvidia, Micron Technology, Texas Instruments et al. That not only would create thousands of good paying and essential jobs but would close a significant national security gap.
We won't single handedly win WWIII either, but we sure don't have to be sitting ducks for powerful countries who would dearly love to do their worst to us if they dared.