"Why did they bother with a navy? They could have just kept a token militia force at home and relied on “free trade” with everybody, including their potential enemies, and everyone would have been rich and happy. /s" Sure, just like America's Founding Fathers, right? ;-)
USS Constitution:
awarded: 1794 under under "isolationist" Founding Father, President Washington.
launched: 1797 under "pacifist" Founding Father, President Adams.
cost: $302,000 equivalent in terms of today's GDP & government revenues to $13 billion!
Sent to fight Barbary Pirates in North Africa: 1803 by that well known "non-interventionist" President Jefferson.
Used to fight the Brits: War of 1812, by that "peace loving" President Madison.
Gorgeous picture. I'm always amazed that people would try to row a becalmed warship out of trouble.
Washington was no isolationist, but a realist, and his statement about "entangling alliances" is usually quoted completely out of context. He was writing at a time when the Republicans (Jefferson's party) wanted to side with the French, and the extreme Federalists sympathized with Britain. Adams was strongly in favor of a navy to protect our interests, esp. against the French. The Republicans sounded a lot like today's loony libertarians.
The OP shows that anyone who wants to carry on peaceful trade better have a strong military. A nation's trade is inevitably attacked in time of war. Our greatest potential enemy, China, is behaving like all the great powers of the past, trying to sew up access to vital raw materials and potentially deny them to us, not engaging in wishful thinking that "free market magic" will always get them what they need.