I was extremely common to find Americans fighting for other coutries in the late 19th century. After the Civil War, there were a buttload of soldiers and officers with no work (and with rapid deflation, no chance of one) they sold their serives around the world. The khedive of Egypt hired two dozen American officers to aid inthe subduing of the Sudan and other locations in the country (much to the dismay of Gen. 'Chinese' Gordon.) Several American fought in the 1877 Meiji Rebelion, in the various Central and South American wars (including the disastrous Walker Incident -- where an American colonel tried to take over Nicaragua [without US support].)
I'm interested in seeing this one.
"War is an ugly thing but not the ugliest of things; the decayed and degraded state of moral and patriotic feelings which thinks that nothing is worth war is much worse. A man who has nothing for which he is willing to fight, nothing which is more important than his own personal safety, is a miserable creature and has no chance of being free unless made and kept so by the exertions of better men than himself."
John Stuart Mill