After the Supreme Court ruled that there is an individual right to bear arms in the Heller case overturning the ban on handguns in Washington, D.C., it was just a matter of time before a legal challenge to gun restrictions would offer the opportunity for the court to expand gun rights to the states. The chance came quickly in the form of McDonald v. Chicago, challenging the city's handgun ban, which was overturned along ideological lines in a 5-4 decision.
The question wasn't so much whether the court would rule that the Second Amendment right to bear arms applies to the states, so much as whether it would do so under the "due process" or "privileges or immunities*" clauses of the 14th Amendment. The latter has been dormant for years as a result of an 1873 ruling that said the "privileges or immunities" clause that was meant to ensure the protections in the Bill of Rights applied to the states didn't. The result was that these rights were "selectively incorporated" over the years through the "due process clause."
What liberals hoped was that the originalists on the court would take the opportunity to revive the original intent of the "privileges or immunities" clause, which would have the effect of cementing gun-rights protections but also strengthen the legal case for liberal causes like LGBT rights, by making the Bill of Rights apply to all the states without the need for "selective incorporation." Instead of taking the "originalist route" and applying the 14th Amendment authors' plain intent, the conservative majority chose a narrow path that strengthens the right to bear arms but gives no opening to those icky rights that might be asserted under a revival of the "privileges and immunities" clause. That's despite the fact that the "privileges and immunities" clause (No State shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States) is pretty clear, you don't even need a oujia board.
Somewhat ironically, Justice Clarence Thomas was the only justice on the court who argued that the "privileges or immunities" clause should be applied. In arguing, as Scott Lemieux notes, that "tradition trumps original intent," the rest of the court again revealed originalism as being as "results oriented" as the activists they rage against so loudly. By avoiding reviving the privileges and immunities clause, the conservative wing of the court basically ensured that judges get to continue selectively deciding which parts of the Bill of Rights count and which don't. As Radley Balko wrote, Justice Antonin Scalia just "acknowledged he doesn’t really agree with his own opinion."
On the merits, based on the previous ruling in Heller, I think this case was rightly decided, if wrongly reasoned. The gun wars are pretty much over, and the gun rights side won. One wonders when they'll will figure it out.
*Correction: "privileges or immunities" clause. The "privileges and immunities" clause is in Article IV, Section 2.