During the time of great industrial growth from the latter part of the 1800's to pre-WWI, millions of immigrants helped bolster the labor needs of the this time of growth and expansion in the United States. Peaking post WWI, the KKK supported a "Nativism" mindset in America and was resurrected during this era to influence others to restrict immigration. Nativism was a political policy of preserving or reviving indigenous cultures. The KKK sought to influence this policy.