European Unionism clashed with brown-turning-black nationalism and irredentism.
"After the Rain" by Sam Vaknin
Alsace and Lorraine are, it is true, no longer in German hands, but ... irredentism has only changed its camp.
"The Inside Story Of The Peace Conference" by Emile Joseph Dillon
Bulgaria, motivated mainly by irredentism, fought on the German side during both world wars.
"Area Handbook for Bulgaria" by Eugene K. Keefe, Violeta D. Baluyut, William Giloane, Anne K. Long, James M. Moore, and Neda A. Walpole