How did south carolina v katzenbach and shelby v holder affect the voting rights act of 1965

In South Carolina v. Katzenbach ( and similarly and much more recently, in 2013, in Shelby County v. Holder) South Carolina filed a complaint  with the Supreme Court challenging the Voting Rights Act as unconstitutionalon respect to state´s rights. Many outhern states follow suit. This provoked the Supreme Court to pass judgement before the elections of 1966, upholding the Voting Rights Act and thus enabling almost a million of African Americans to register to vote.

a. competition between france and england for land and power

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