The Senate was originally intended to be something of a brake on the Legislative process, and to be acting on behalf of state governments. The founders were not particular fans of democracy, and so we have a number of undemocratic provisions in the Constitution. Among these:
-
The Electoral College
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Selection of Senators by State Legislatures
(deleted in the XVIIth Amendment) -
Lack of an initiative process for amending the constitution.
(Given the complete SNAFU the initiative process has made of the
California State Constitution, I tend to agree with this one.) -
Referral of Amendments to State Legislatures rather the People.