The first one is the believe that somehow the Second Amendment invalidates article III, Section iii of the US Constitution.
Or that a document that begins:
We the People of the United States, in Order to form a more perfect Union, establish Justice, insure domestic Tranquility, provide for the common defence,promote the general Welfare, and secure the Blessings of Liberty to ourselves and our Posterity, do ordain and establish this Constitution for the United States of America.somehow contains the seeds of destruction of the nation.
The US Constitution was written as a response to Shays' Rebellion and a read of what the drafters thought about that event should eliminate any doubt that the Constitution somehow condones rebellion if it isn't clear enough from the Constitution itself.
Nevermind that the military structure envisioned by the founders which was supposed to be guaranteed by the Second Amendment is as non-existent as the American Dream.
But this is what happens when one chooses to ignore the purpose of the Second Amendment ("A well regulated Militia, being necessary to the security of a free State") and call it somehow meaningless. Saying that a clause in the constitution which is somehow "mere surplusage" is a statement which makes judicial review meaningless (see Marbury v. Madison, 5 U.S. 137 (more) 1 Cranch 137, 2 L. Ed. 60, 1803 U.S. LEXIS 352).
If the people who make idiotic statements like this would take a few moments to consider the ramifications of the Alexandria shooting, then we might actually get somewhere. They need to understand one person's freedom can be seen as another's tyranny. One person's freedom fighter is another's terrorist.
They can't go making statements like that and not understand that they may have just put a target on their OWN backs.
Even more importantly, one cannot have a serious war on terrorism and make weapons easily accessible to your enemy.
If anything, the Second Amendment's "well regulated" needs to be brought into the debate. And it fucking well doesn't mean "well-trained", but under strict civilian control (the real issue of the Second Amendment is civilian control of the military, not personal weapons--that is exactly what you will find if you actually do some thinking and stop parroting idiotic statements which are detrimental to the constitutional structure of the US).
If gun rights are enumerated, then they are under very tight control. As State v. Buzzard, 4 Ark. (2 Pike) 18 (1842), pointed out about the absurdity of the individual right assertion:
However captivating such arguments may appear upon a merely casual or superficial view of the subject, they are believed to be specious, and to rest upon premises at variance with all the fundamental principles upon which the government is based; and that, upon a more mature and careful investigation, as to the object for which the right was retained their fallacy becomes evident. The dangers to be apprehended from the existence and exercise of such right, not only to social order, domestic tranquillity and the upright and independent administration of the government, but also to the established institutions of the country, appears so obvious as to induce the belief that they are present to every intelligent mind, and to render their statement here unnecessary.The US Supreme Court said in Presser v Illinois, 116 U.S. 252, 6 S.Ct. 580, 29 L.Ed. 615 (1886):
It is undoubtedly true that all citizens capable of bearing arms constitute the reserved military force or reserve militia of the United States as well as of the states, and, in view of this prerogative of the general government, as well as of its general powers, the states cannot, even laying the constitutional provision in question out of view, prohibit the people from keeping and bearing arms, so as to deprive the United States of their rightful resource for maintaining the public security, and disable the people from performing their duty to the general government. But, as already stated, we think it clear that the sections under consideration do not have this effect...US v. Miller was not helpful to the revisionist agenda of the Heller-McDonald decisions because it made clear that the Second Amendment has the "obvious purpose to assure the continuation and render possible the effectiveness of such forces (organised in accordance with USC Article I, Section 8, Clauses 15 & 16), the declaration and guarantee of the Second Amendment were made. It must be interpreted and applied with that end in view."
It is undoubtedly true that all citizens capable of bearing arms constitute the reserved military force or reserve militia of the United States as well as of the states, and, in view of this prerogative of the general government, as well as of its general powers, the states cannot, even laying the constitutional provision in question out of view, prohibit the people from keeping and bearing arms, so as to deprive the United States of their rightful resource for maintaining the public security, and disable the people from performing their duty to the general government. But, as already stated, we think it clear that the sections under consideration do not have this effect.
It cannot be successfully questioned that the state governments, unless restrained by their own constitutions, have the power to regulate or prohibit associations and meetings of the people, except in the case of peaceable assemblies to perform the duties or exercise the privileges of citizens of the United States, and have also the power to control and regulate the organization, drilling, and parading of military bodies and associations, except when such bodies or associations, are authorized by the militia laws of the United States. The exercise of this power by the states is necessary to the public peace, safety, and good order. To deny the power would be to deny the right of the state to disperse assemblages organized for sedition and treason, and the right to suppress armed mobs bent on riot and rapine.
The Second Amendment is a victim of desuetude and it was Scalia's job to have declared it such. But it is now the public which must come to the realisation that the Second Amendment serves no purpose in modern society.
Before it ends up being the self-destruct button for the United States.
 Military regulations are not a drill manual, but the rules of conduct. And while we are discussing Article I, Section 8, we should mention clause 14 which states:
"The Congress shall have Power To ...make Rules for the Government and Regulation of the land and naval Forces...."
Anyone with a shred of familiarity with the US Constitution should be ashamed at pushing the absurdity of the revisionist "individual right" interpretation of the Second Amendment as being so far removed from the text to be an obvious non-sequitur.
See also, www.heritage.org/constitution/#!/articles/1/essays/54/military-regulations
 " the declaration and guarantee of the Second Amendment were made"--this means that the Second Amendment MUST be read as a whole. That basically invalidates the bullshit spouted by the Heller and McDonald decisions and the pseudoscholarship which would remove the Second Amendment from its Constitutional context.