I'm not doubting your history knowledge here... but what are we defining as "involvement" here, is that a formal or even informal declaration from the Polish government or simply people of Polish decent/immigrants involved in our conflicts? Or something in between?
I am certainly not a history student in those things but a bit of Googling and wikipedia reading leads me to believe that their involvement in say, the Mexican-American war... or the Civil War... and a few others... may have involved people of decent from there or 1st generation immigrants but that was about all.
So tell me more, inquiring minds would like to know