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Are the readers this poorly versed in Contitutional history that they lack even basic knowledge that should have been mastered in High School civics?
"Xanthro, thanks for all the research. quite helpful. And in fact those 'penumbras' are pretty questionable, one could even say 'shady'"
If we skipped civics perhaps we should at least learn to Google.
Article 1 Section II
The House of Representatives shall be composed of Members chosen every second Year by the People of the several States,
Article 2 Section I
Each State shall appoint, in such Manner as the Legislature thereof may direct, a Number of Electors, equal to the whole Number of Senators and Representatives to which the State may be entitled in the Congress: but no Senator or Representative, or Person holding an Office of Trust or Profit under the United States, shall be appointed an Elector.
http://www.archives.gov/national-archives-experience/charters/constitution_transcript.html
So, yes you have the Constitutional Right to vote for Representatives, but you do not for President. The State legislature can chose how the Electors are selected.
Law upheld by the Supreme Court in United States v. Reese.
The reason why amendments address the issue of voting is because the Constitutional right to vote has been expanded, from only white males, to all males, to all adults, to all persons 18 or older.