Note that after the Immigration and Nationality Act Amendments of 1965 the dots from Mexico start to become a solid line.

Also, note the most quoted quote concerning the new law, Senate Immigration Subcommittee Senator Edward Kennedy remarked that "the bill will not flood our cities with immigrants. It will not upset the ethnic mix of our society. It will not relax the standards of admission. It will not cause American workers to lose their jobs." (U.S. Senate, Subcommittee on Immigration and Naturalization of the Committee on the Judiciary, Washington, D.C., Feb. 10, 1965.

Every normal man must be tempted, at times, to spit on his hands, hoist the black flag, and begin slitting throats. H. L. Mencken