Vietnam stopped military adventurism for a good generation until we were forced into the Gulf War. Now we have watched another cycle of been bled out in Iraq and Afghanistan. That is three wars in which military power proved impossible to impose a peace or a satisfactory outcome.
They honestly have never understood just how lucky they were to have Mac Arthur operate the Japanese reconstruction in particular. Just that has been sorely missing everywhere else.
Iraq fell apart under reconstruction through blindingly stupid mistakes by folks whose interest supported neither US or Iraqi interests.
No one gets it but the USA has today a natural ally in Russia to accomplish the following:
1 Forming an United States of Europe with corrected borders including Russia and accepting Eastern Christianity as a dominant evangelizing force likely naturally subsuming Catholicism and other forms.
2 It can be expected that leadership will be initially Russian but power will also be moral at that level with real decisions been influenced by the rule of twelve and a range of legistlative structures.
3 Confront Islam and absorb it though natural conversion driven by simply insisting that everyone reads and understands the koan and the inherent conflicts with Christian teaching. In that situation is is hard to see Islam as sustainable.
That is the historical trend line and it is coming quickly.