Amicus briefs in Chicago case rolling in
Here's the Academics for the Second Amendment amicus. And here's the Congressional amicus, signed by 58 Senators and 251 Congressmen, and filed by Paul Clement. As Solicitor General, in Heller Clement had argued for a lower standard of review; you don't see that here!
Our theme in the A2A brief was that talk of "incorporating" a right is a bit misleading. It implies the question is whether the 1866 Framers and ratifiers meant to apply a 1789 understanding to the States. The real question is the intent and understanding of 1866-68. Americans of this period may have thought they were speaking of the 1789 intent, but actually their understanding of rights was far broader. This is especially so in the case of the right to arms. Two major changes here.
In 1789, many spoke of it in the context of a universal, mandatory militia that was absolutely "necessary to the security of a free state." But between 1816 and 1850, the mandatory militia statutes were repealed, and the Republic did not fall. In 1789, standing armies and select militias were the path to dictatorship; in 1866, millions of Americans had served, select militias were everywhere, and they had saved rather than destroyed the Republic. The 1866 Framers as often as not omitted the militia preface when quoting the Second Amendment, and went straight to the right to arms.
Conversely, conflicts over abolitionism, "Bloody Kansas," and now attempts to disarm Blacks and unionists, caused the right to arms to be seen as a purely individual right -- the right to shoot an intruder at the door, even if the intruder worked for the State. The same Congress that passed the Freedmen's Bureau Act (explicitly referring to the "constitutional right to arms") and the 14th Amendment also enacted laws disbanding most of the southern militias, precisely because they were disarming freedmen.