Second Amendment case law has been mired in confusion for many years. Many of the primary cases were decided in the years after the Civil War, after passage of the 14th Amendment. The legal doctrine of “incorporation” by means of the 14th Amendment began to develop several years after Miller v Texas (1894) and other gun cases decided prior to 1894. The concept of incorporation is important to undertsanding most modern Constitutional law, especially where the Bill of Rights is involved.
A great deal of the material herein has been gleaned from Stephen P. Halbrook, Cynthia Leonardatos and David B. Kopel's excellent article entitled "Miller v Texas: Police Violence, Race Relations, Capital Punishment, and Gun-Toting in Texas in the Nineteenth Century and Today."

Incorporation is the process of judicial reasoning that determines which Constitutional guarantees are enforceable by the federal courts against the states. Prior to passage of the 14th Amendment, there was no argument about whether any provisions of the Bill of Rights applied to the states. The Amendments to the U.S. Constitution only restricted the federal government- until the 14th Amendment was ratified.
After the Civil War, Southern States passed laws that prohibited blacks from engaging in activities that were legal for other citizens; e.g., ownership of firearms and voting. During the debates leading up to the passage of the 14th Amendment, Southern members of Congress (mostly Democrats) argued that the 14th Amendment would permit blacks to bear arms. The Northerners (who tended to be Republicans) agreed that gun rights would be extended to blacks by means of the 14th Amendment.

Bear in mind that most state constitutions have provisions that mirror the Second Amendment. The states' constitutional guarantees of the right to keep and bear arms are important to note because, during the legislative debates pertaining to passage of the 14th Amendment, some members of Congress may have anticipated at the time that the federal Bill of Rights would apply directly to the states while others may have viewed the state protections as privileges and immunities (see text of 14th Amendment in red below) that would gain additional federal protection that did not exist prior to the 14th Amendment.
Thus, when the 14th Amendment was enacted, no serious person disputed whether owning and using weapons was a right that belonged to an individual citizen as opposed to the relatively modern "collective rights" theory" promoted by the Nixon administration and various proponents of gun control that have followed.

In the 1900s, courts began a selective process of choosing which of the substantive provisions of the Bill of Rights would be incorporated; i.e., which federal rights would be enforced against the states by virtue of the 14th Amendment:
Section. 1. All persons born or naturalized in the United States and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside. No State shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States; nor shall any State deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws.
This process of incorporation included the concept of “substantive due process”. Ironically, the early “substantive due process” cases had to do with child labor laws and workman’s compensation and other progressive efforts to ameliorate the harshness of the conditions under which many worked in the early Twentieth Century. Conservative Republican judges knocked out such progressive state legislation with decisions holding that freedom of contract (a liberty and property interest under the 14th Amendment) was incorporated against the state laws via the 14th Amendment.

In law school, lawyers learn that the question of whether a Bill of Rights provision should be enforceable against the states is determined by whether the right is “fundamental to a well-ordered system of liberty”. The fact that some provisions of the Bill of Rights may apply to the states while others do not raises the issue of whether any right is more fundamental than the right of a citizen to defend one’s self and others.
In U.S. v Cruikshank, whites disputing an 1872 election not long after passage of the 14th Amendment burned down a Louisiana courthouse. Cruikshank was a white man convicted of conspiring to deprive armed blacks of their right to peaceably assemble and bear arms; i.e., rights protected by the U.S. Constitution. The Supreme Court held that the federal Enforcement Act under which the defendant was convicted was unenforceable because certain rights are fundamental and existed prior to the federal Constitution (if it seems confusing, it is just as confusing to lawyers). This holding has the familiar ring of rights that are “fundamental to a well-ordered system of liberty” but Cruikshank did not incorporate federal Constitutional protections. In other words the Cruikshank court did not guarantee individuals protection against state laws that violate the federal Constitution.

Subsequent decisions have been clouded by what exactly the Court decided in Cruikshank. The best interpretation seems to be that, since there was no state action (none of the actors were acting on behalf of the State of Louisiana), it was a purely state matter in which federal Constitutional rights are not applicable. Cruikshank is often cited, however, to stand for the premise that the Bill of Rights is not enforceable against the states. Try to tell that to Planned Parenthood or just suggest such a thing during your upcoming Senate confirmation hearings and you are guaranteed to be run out on the Democratic Party's rail.

Roe v Wade and many of the other pet projects of our liberal elite are premised on “substantive due process” as reincarnated under a line of cases starting with Griswold v Connecticut in which the Court descried a new privacy interest that emanated from the substance of various provisions within the Bill of Rights. This was the case that brought the term “penumbra” to the forefront of Constitutional jurisprudence:
“The foregoing cases suggest that specific guarantees in the Bill of Rights have penumbras, formed by emanations from those guarantees that help give them life and substance. Various guarantees create zones of privacy. The right of association contained in the penumbra of the First Amendment is one, as we have seen. The Third Amendment in its prohibition against the quartering of soldiers "in any house" in time of peace without the consent of the owner is another facet of that privacy. The Fourth Amendment explicitly affirms the "right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures." The Fifth Amendment in its Self-Incrimination Clause enables the citizen to create a zone of privacy which government may not force him to surrender to his detriment. The Ninth Amendment provides: "The enumeration in the Constitution, of certain rights, shall not be construed to deny or disparage others retained by the people."
The Fourth and Fifth Amendments were described... as protection against all governmental invasions "of the sanctity of a man's home and the privacies of life."
We have had many controversies over these penumbral rights of "privacy and repose." These cases bear witness that the right of privacy which presses for recognition here is a legitimate one.”
GRISWOLD v. CONNECTICUT, U.S. Supreme Court
381 U.S. 479 (Decided June 7, 1965).
The old “substantive due process” is now a kinder and gentler rainbow of promise that both confers and guarantees the right of a woman to dispose of a child at any time during the process of conception, gestation or even birth without her parents’ permission and regardless of whether she is of the age of consent; the same Constitutional privacy "emanations" guarantee the right of consenting adults to commit sodomy and the right to purvey pornography- all thanks to the penumbra emanating from the various components of the "living" Constitution.
The Griswold court and its successors breathed life into the Constitution, according to many lawyers and most law professors, because they found emanations that were never enumerated within the previously dead letters of the text.
Contrary to some scholarly opinion, the holding in Cruikshank hardly could have been that the 14th Amendment does not incorporate the Second Amendment because, as emphasized above, the courts only started recognizing incorporation as a theory eleven years later in the line of cases cited in Adamson v California, 332 U.S. 46 (1947) by Justice Black in his dissenting opinion:
“Later decisions of this Court have completely undermined that phase of the Twining doctrine (rejecting application of the Fifth Amendment to the states) which broadly precluded reliance on the Bill of Rights to determine what is and what is not a "fundamental" right. This Court has now held that the Fourteenth Amendment protects from state invasion the following "fundamental" rights safeguarded by the Bill of Rights: right to counsel in criminal cases, Powell v. Alabama, 287 U.S. 45 (1932) freedom of assembly, De Jonge v. Oregon, 299 U.S. 353 (1937), the right of an accused in a criminal case to be informed of the charge against him, see Snyder v. Massachusetts, 291 U.S. 97 (1934), the right to receive just compensation on account of taking private property for public use, Chicago, B. & Q. R. Co. v. Chicago, 166 U.S. 226 (1897).
The Court applied the First Amendment to the states in Everson v. Board of Education, 330 U.S. 1 (1947); Board of Education v. Barnette, 319 U.S. 624, 639 (1943); Bridges v. California, 314 U.S. 252, 268 (1941).
The next Second Amendment case, Presser v Illinois (1886), has also caused disagreement among subsequent legal scholars. The issue in Presser was whether an Illinois statute banning armed parades infringed on the right of labor union members to keep and bear arms while demonstrating to strike breakers and goons that they would not be intimidated. The Court’s decision was probably based on common law precedent prohibiting armed assemblies of men. The Court held that the Second Amendment only restricted the federal government; thus adumbrating the previous holding in Cruikshank eleven years prior to Chicago, B. & Q. R. Co. v. Chicago, the first case recognizing the concept of incorporation via the 14th Amendment. Nevertheless, it was recently common to see judges and legal scholars citing these earlier cases as standing for the premise that the Second Amendment is somehow a dead letter under the law. At this time in legal history, almost every right imaginable has been incorporated by means of the 14th Amendment analysis outlined above, including rights that are not even found in the text of the document. Apparently only the Second Amendment is not a fundamental right.
This brings us to Miller v Texas, an 1894 case. Franklin Miller, a white man in Dallas, Texas, had neighbors that believed he should be incarcerated as a felon because he was living with a black woman. Mr. Miller was charged with miscegenation, punishable by a prison sentence. He armed himself and began making statements that threatened certain police officers. The officers attempted to serve Miller (possibly with their weapons drawn) in further criminal proceedings based on allegations that he was illegally carrying arms in public.
When the officers approached Miller, shooting commenced, resulting in a dead officer and a near lynching. There were many conflicting versions of who shot first and whether Franklin Miller was defending himself from the constables; Miller was convicted of murder and sentenced to die. Miller lost his appeal to the Texas Court of Appeals in 1893 and he petitioned for a rehearing. His Petition for Rehearing raised for the first time the issue that went to the U.S. Supreme Court; i.e., whether the Reconstruction Act of 1871 (restricting his right to carry weapons) violated the Second, Fourth and Fourteenth Amendments.

The Miller court held that “… it is well settled that the restrictions of these amendments operate only upon the Federal power, and have no reference whatever to proceedings in state courts.”
Furthermore, the Court held that a ban on concealed weapons is an inherent exception implied by the Bill of Rights (possibly a precedent for the “emanations” from Griswold?)

The Court also cited the fact that the issues were not raised at trial and rejected Miller’s claims without deciding the issue of how the Second Amendment applied to the states, leaving the question open.

SCOTUS is due to decide DC v Heller this month:
Washington, DC has one of the most restrictive gun laws in the country, the D.C. statute is the focus of a March 18 U.S. Supreme Court hearing that marks the most significant case on gun control in decades. With Heller as plaintiff, it is the first test since 1939 of whether the Second Amendment supports an individual's right to bear arms and not just a state's right to form a militia. It is a crucial distinction. A ruling in favor of the individual right could trigger a wave of constitutional challenges to gun control laws nationwide. And it could suddenly bring a volatile issue—one particularly uncomfortable for Democrats—into play during a presidential election year.
The Heller case will be the first case to decide whether the Second Amendment is an individual right but will not decide whether the right to keep and bear arms is incorporated against the states via the 14th Amendment. The chances are that most state and local gun restrictions will not be immediately affected by the Court’s decision because, for one thing, Washington DC is not a state.
Dick Heller, a longtime resident of the District of Columbia, carries a handgun for his job as a private security guard. But at the end of his shift, he packs up the .38 revolver and stashes it in a vault. He would like to keep a gun for protection at his Capitol Hill home, where he has endured the sound of gunfire for years. But he can't, because D.C. law forbids it. "They give me a gun to protect them," he says of the government, "but I'm a second-class citizen when I finish work."