Can forced assimilation policies successfully integrate immigrant groups? This paper examines how a specific assimilation policy – language restrictions in elementary school – affects integration and identification with the host country later in life. After World War I, several US states barred the German language from their schools. I find that affected individuals were less likely to volunteer in WWII and more likely to marry within their ethnic group and to choose decidedly German names for their offspring. Rather than facilitating the assimilation of immigrant children, the policy instigated a backlash, heightening the sense of cultural identity among the minority.