Earlier quoted context omitted.
when you can just trade Peacetime commerce requires free waterways. Everyone can "just trade" because the U.S. Navy has guaranteed free navigation of the seas since Bretton Woods[1]. When America withdraws from its security obligations, others will fill the vacuum, with all the uncertainty that implies. A national leader who fears being cut off from essential resources will very logically view war as an option. Edit:…
Cut off by who though, and why? Denying what? These questions don't exist in a vacuum, and wars are terrible ways to secure resources as the US's adventurism in the Middle East has shown. If your goal is say, oil, it's still cheaper to just buy it.
Perhaps US action in ME gasp isn't to seize physical resources then?