A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed.
The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.
Do you note a common phrase in these two Constitutional amendments? In fact, the words "the people" are used nine times in the Constitution of the United States. Is the meaning of these words constant throughout the document? Does the meaning vary?
The phrase is used regarding selection of Congressmen (Article I, Section 2) and Senators (17th Amendment). Take note that even in these two instances, the meaning of the phrase has evolved.
The 17 the Amendment states "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."
Note that in that amendment, the definition of "the people" who do the electing is left to the states. That is the same phrasing as in Article I, Section 2. In fact, the 15th Amendment changed the meaning by, expanding the voting public, as did the 19th Amendment, which granted women the right to vote. (On a sober note, the 19th Amendment lies between the 18th and 21st, which began and ended prohibition. )
The 26th Amendment set the minimum voting age at 18, which again changed the meaning of "the people".
When it comes to voting, one would be hard pressed to prove via the Constitution that voting for President is even required. (Choosing electors is required, but the manner is unspecified).
Speaking of voting, those living in Washington D.C. do not have representatives in either house of Congress. Do they have to pay income taxes? Is that not taxation without representation, one of the items this country was created to avoid? Are D.C. residents really included in "the people"?
Indeed, there are inconsistencies within our Constitution. It is not a complete description of the way we need to live, but at least it has a built-in process to correct itself.
Remember: those who originally approved 2nd Amendment did not allow women or people of color to vote, left it to the states to decide any age limits, and actually created a document in which slavery was okay. Did the authors of the original Constitution make mistakes? You bet they did.
Now what about that Second Amendment?