Contemporary American conservatism has a deep commitment to originalism as a means of interpreting the Constitution. We need to understand the words of the Constitution, they argue, in the sense that they were intended by the framers.
The Constitution itself was adopted in 1787 setting out the structure of the government of the United States of America. Two years later it was amended with the Bill of Rights, ten declarations asserting freedoms necessary to maintain that form of government in reality. The first amendment, those freedoms which were deemed most vital to a functioning democracy were freedom of speech, freedom of peaceable assembly, freedom of the press (a form of speech), freedom to petition the government for redress of grievances (again a form of speech), and freedom of religion (which in its actual manifestation of congregating for prayer is a combination of assembling for speech). These were seen as establishing the preconditions for the possibility of democracy. Without these, you would not have a pluralistic, maximally rational, Enlightenment-inspired democratic system that is functional.
Then, they included amendments that would guarantee that these foundational freedoms could not be tampered with. What is the first most important protection for the basic operations of democracy?:
"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."
What is going on here? Why is this the most important issue that has to be set out to make sure our democratic government maintains itself? There are two possible threats to it. First, there is the need for defense of the country against external invaders and this requires an armed force. But this armed force could take one of two forms, either a professional standing army under the control of the government or a militia in which the force ceases to be during peace time, but assembles when necessary during invasion. The framers clearly opt for the latter. Why?
The decision to have a militia based defense force instead of a standing army is to both protect the borders from outside and freedoms established in the first amendment from inside. If one is exercising one's freedom of speech and says something unpopular, the discussion might go something like this:
"Shut up."
"No."
"I said shut up."
"And I said no."
"Shut up or I'll shut you up."
"Yeah, you and what army?"
Ooooooooh. So, that's why the framers didn't want a standing army. If the President as Commander-in-Chief has an armed force under his control that makes him more than first amongst equals -- he's no longer equal. That sort of power will inevitably be used to silence critics, but the criticism is essential to a healthy democracy which is why the first amendment guarantees it.
But if we need a military and it cannot be a standing army, then it must be a militia of citizen-soldiers who are citizens under normal circumstances and soldiers when needed to defend the borders. The framers' logic behind the 2nd amendment is:
1) We need a military for security and it could be either a standing army or a militia-based force.
2) We don't have a standing army if and only if we do have a militia.
3) A militia requires the citizens to have quick access to arms.
4) Citizens will have quick access to arms if they have the right to own them.
5) We don't have a standing army.
Therefore, we need the citizens to have the right to bear arms.
The framers' intent in declaring a right to bear arms was to protect both the country from other governments' attempts to invade and to make sure our government doesn't have the means to silence speech by force or threat.
But we decided that the framers' notion didn't work in the real world and we amended our government's structure to allow for professional soldiers in a standing army. No problem there, the framers allowed for changing the structure of the government through several different processes. But the 2nd amendment still stands as it is and by the originalist reading, must remain true to the writers' intended meaning. As such, the above argument still stands, but is altered so that premise 5 is false. But if 5 is false then by 2, we have no militia-based system and thus the argument for an armed citizenry it rendered moot. It is no longer operative because by the framers' reasoning -- which under the originalist reading is sacrosanct -- the preconditions necessitating the right no longer exist.
So, it seems like conservatives have one of three options:
A) Give up the standard understanding of the 2nd amendment as providing them with the right to own personal firearms.
B) Keep that right as it is currently understood, but zero out the military budget and disband the Army, Navy, Air Force, and Marines.
C) Keep both the right to bear arms and the military as is, but give up originalism, thereby contending that the Constitution is a living document whose meaning needs to be understood in light of the current context.
If they go with C, then that forces them to surrender the objections they have to the reading of the Constitution which grants us the right to privacy which is the basis for the decision in Roe v. Wade. If conservatives want to keep their guns and the military, then they have to admit that they were wrong in their arguments against the legal permissibility of abortion. It seems, then, that you cannot consistently hold three of the marquis issues underlying contemporary conservatism. Here's three, pick two.