None. While in general, liberal Democrats by and large fondly wish the Second Amendment didn't exist, no one has ever seriously pursued an amendment that would repeal it.
The Electoral College does not make or repeal amendments to the Constitution.
Yes, by the adoption of another Amendment using the same process required for all amendments. The 21st Amendment was adopted to repeal the 18th amendment.
The purpose of the 20th amendment was to deal with the repeal of prohibition and the 21st amendment focused on limits on presidential terms.
Because the need to "repeal" amendments was sometimes necessary and desired by the people, as in the 18th amendment.
The Democrats want to gun control to safeguard the lives of American citizens. Many citizen, like the innocent children last year are losing lives as a results of the uncontrolled guns.
Senator John J. Blaine, (R) Wisconsin sponsored the 21st Amendment to the US Constitution to repeal the 18th Amendment (commonly referred to as prohibition).
Constitutional issues, repeal the Seventeenth Amendment to the Constitution to restore States' rights by returning the power back to the legislatures of...
It can only be changed by passing another constitutional amendment. The best example of this is the 18th amendment, which was later overturned by passage of the 21st amendment. (These amendments related to prohibition and then the repeal thereof.)
The way the constitution works, you do not just "change an amendment." You can only repeal or change what an earlier amendment with another amendment. An example of repealing an earlier example is how the 21st Amendment nullifies the 18th Amendment (Prohibition). This is also the case with many amendments that had mentioned slavery and how they were altered through new amendments. On a side note, if you meant to say "How many times has the Constitution been changed by the Amendments" then your answer is 27. As the purpose of the amendments was to keep the Constitution as a living document and prevent it from becoming outdated and irrelevant in some cases.
Because the need to "repeal" amendments was sometimes necessary and desired by the people, as in the 18th amendment.
Repeal
Amendments are additions or clarifications. When a constitutional amendment is accepted and enacted, it effectively adds its contents to the constitution, or clarifies points set forth in either the constitution or another amendment. In the Constitution of the United States of America, numerous amendments have been accepted, some shortly after the document was drafted. Effectively, the Constitution served as the foundation, the framework for the ideals of the government. Amendments were proposed, and some added, to expand upon the Constitution's intent. The first ten constitutional amendments, collectively called the Bill of Rights, was completed roughly a decade after the Constituton was adopted. Amendments can be removed. The 18th Amendment was ratified in 1919, and banned alcohol in the United States. This period, called Prohibition, ended in 1933 when the 21st Amendment was passed. The sole purpose of the 21st Amendment was to repeal the 18th Amendment. In summary: to amend any document, constitutions included, means to modify, add, or clarify the document.