Seventeenth Amendment
The Senate of the United States shall be composed of two Senators from each State, elected by the people thereof, for six years; and each Senator shall have one vote. The electors in each State shall have the qualifications requisite for electors of the most numerous branch of the State legislatures.
When vacancies happen in the representation of any State in the Senate, the executive authority of such State shall issue writs of election to fill such vacancies: Provided, That the legislature of any State may empower the executive thereof to make temporary appointments until the people fill the vacancies by election as the legislature may direct.
This amendment shall not be so construed as to affect the election or term of any Senator chosen before it becomes valid as part of the Constitution.
This was ratified in 1913. It replaces the process of state legislatures picking U.S. Senators with a process of democratic election the people.
The Senate, which was comprised of senators selected by state legislatures rather than democratically elected by the people, refused for years to pass this amendment. The states resorted to the alternative mechanism for amendment in bypassing Congress and passing resolutions calling for a constitutional convention. When nearly enough states (2/3rd of the United States) had passed resolutions for a constitutional convention, the Senate averted a constitutional convention by finally passing this amendment and sending it to the states for ratification.
Amendments to the Constitution of the United States of America Bill of Rights:
1 - Freedom of speech, press, religion, etc.
2 - Right to bear arms
3 - Quartering of soldiers
4 - Warrants
5 - Due process
6 - Right to a speedy trial
7 - Right by trial of a jury
8 - No cruel or unusual punishments
9 - Unenumerated rights
10 - Power to the people and states
11 - Immunity of states to foreign suits
12 - Revision of presidential election procedures
13 - Abolition of slavery
14 - Citizenship
15 - Racial suffrage
16 - Federal income tax
17 - Direct election of the United States Senate
18 - Prohibition of alcohol
19 - Women's suffrage
20 - Terms of the presidency
21 - Repeal of Eighteenth Amendment
22 - Limits the president to two terms
23 - District of Columbia Voting for President
24 - Prohibition of poll taxes
25 - Presidential disabilities
26 - Voting age lowered to 18
27 - Variance of congressional compensation