The need isn’t only driven by our enemies having critical places in our supply chains. Our friends and would-be friends have similarly critical places, and they act as enthusiastically for their own self interest as we do. And those self interests can conflict.
Take India and hydroxychloroquine. India has decided to ban the export of any of its production of the drug. Worldwide demand is expanding greatly in response to its apparent (though not yet clearly demonstrated) effectiveness in treating Wuhan Virus infections, while production capacity has not—cannot—expand as rapidly to meet that demand. India has a very large population with diseases for which on-label use is wholly warranted. India’s ban is not borne of enmity toward us but of national need and so self interest.
We can retaliate against India and its ban, as President Donald Trump has threatened to do, but that sort of response doesn’t address the underlying problem (it should be noted that retaliations prove unnecessary; India has enacted an exception to its ban that allows export to us). We need to be able to produce our own hydroxychloroquine from scratch, entirely domestically. We still should get the drug, and intermediate production chemicals, from the most efficiently done sources, including internationally, but we absolutely need to have an ability to produce at least some entirely domestically. That would give us a core capability from which to expand, should a need arise, rather than leave us to do without or vulnerable to extortion, as our enemies will apply.