Boiling it down to basics, you basically need to keep the supply chain of items flowing at the lowest possible cost and put contingencies in place to minimize disruptions.
So, this isn't only a problem for tRump, most Republicans govern this way.
I had two bosses in my first five years of college who followed the ignorant tRump approach. We control the purse strings so F every supplier, (unless they provide good perks to them personally) and force cost reductions etc, down their throats.
So what quickly happens is you might beat down a supplier, but any issue with the contract becomes a sticking point and issue. So a new better product comes out from that supplier, ah, that wasn't in the contract. Your company is can buy the product at list, or list plus for the next two years. Oh, we had a hurricane in our Puerto Rico facility, sorry capacity decreased by 15% so under the Force Majeure clause kicks in, we can't make your deliveries for the next 90 days, SORRY!
You have basically pissed off a trading partner and they are looking at any way, any possible way to bend your company over. So you end up with higher prices, more disruption, and tons of wasted time fixing things.
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