It's definitional

In a republic, voting is an earned privilege, not a right. -rickl
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Maybe you mean it SHOULD be an earned privilege. It certainly isn't in this republic. -Chi-Town Jerry
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It's definitional. When (if) voting again becomes a privilege v a right, you have a Constitutional Democratic Republic. Otherwise, you just have a Democracy which as Al d'T said, lasts 'til The People realize they can vote themselves money...