The Chinese Exclusion Act started in 1882, and it was repealed/ended in 1943. This is the number of years the US government denied any Chinese immigrants into the United States:

41

51

61

71

the monroe doctrine is the best known u.s. policy toward the western hemisphere. buried in a routine annual message delivered to congress by president james monroe in december 1823, the doctrine warns european nations that the united states would not tolerate further colonization or puppet monarchs.

immigrants from northern and western europe continued coming as they had for three centuries, but in decreasing numbers