This week’s historic Supreme Court case on gun rights has pivotal implications for Elena Kagan’s Supreme Court confirmation hearings. From now on, the biggest battles over the Second Amendment will be won or lost in the Supreme Court.

In the 2008 case D.C. v. Heller, the Supreme Court held 5−4 that the Second Amendment secures an individual right to own a gun. But because the Bill of Rights only applies directly to federal laws (such as those in D.C.), Heller only made the Second Amendment a right against the federal government.

On June 28 of this year in McDonald v. Chicago, a new 5−4 Supreme Court decision held that the individual right to own a gun from Heller is a fundamental right, and as such extends through the Fourteenth Amendment as a right against state and local governments as well.

Justice Stephen Breyer wrote a dissent that Justices Ruth Bader Ginsburg and Sonia Sotomayor joined in full. (Justice John Paul Stevens wrote a separate dissent.) That dissent contains a telling revelation about Barack Obama’s Supreme Court.

When Sotomayor was nominated for the High Court last year, she was asked by Judiciary Committee Chairman Pat Leahy (D−VT) whether after Heller it is now a matter of settled law that the Second Amendment secures an individual right to own a gun. Her answer was clear and direct: “Yes, sir.”

Yet Monday, Justice Sotomayor joined in full the following statement: “I can find nothing in the Second Amendment’s text, history, or underlying rationale … to protect the keeping and bearing arms for private self-defense purposes.”

The dissent went on to argue that the Court should “reconsider” the Heller decision, meaning that the Court should overrule Heller‘s holding that the Second Amendment applies to American citizens.

This is completely consistent with Sonia Sotomayor’s record as a Second Circuit judge, where she repeatedly ruled against gun rights. She argued that the Second Amendment does not apply to individuals, does not apply to states, and that any gun-control law should be upheld if it’s rational. (She then added that because guns are deadly, any law restricting them is rational. Hence, all gun-control laws are automatically constitutional, even complete bans.)

Fast forward to President Obama’s new Supreme Court nominee, Elena Kagan. She too has a record when it comes to the Second Amendment.

First, when she was clerking for Justice Thurgood Marshall in 1987, a D.C. resident challenged the D.C. gun ban (the one later struck down in Heller), arguing that it was unconstitutional for D.C. to bar him from having a gun in his home for self-defense. Kagan wrote to Justice Marshall that, “I’m not sympathetic” to his belief that the Second Amendment is an individual right.

Second, when she was working as a lawyer in the Clinton White House, another White House staffer described Kagan as being “immersed” in Bill Clinton’s gun-control policy efforts. (Bill Clinton was the most anti-gun president in history before Barack Obama came along.)

And third, just this year when the McDonald case was argued before the Supreme Court, Solicitor General Kagan refused to file a brief either way to express the opinion of the United States government on this monumentally-important case. Contrast this to 2008, when Bush Solicitor General Paul Clement not only filed a brief in Heller, but also asked for time during oral argument.

The Left tries to argue that the solicitor general’s office has a tradition of not weighing in on whether Bill of Rights provisions apply to the states out of respect for state sovereignty. Aside from the fact that this would be the first time the Obama administration has shown the slightest regard for state sovereignty, that explanation just doesn’t wash. If the question before the Court was whether the First Amendment Religious Establishment Clause or the Eighth Amendment ban on torture applies to the states, I seriously doubt that this administration would quietly sit on the sidelines in solemn reverence for state sovereignty.

A more likely explanation is that Kagan was aware that President openly supports the Chicago gun ban, and she didn’t want to oppose the man considering her for the Court. That, and–more importantly–she’s still “not sympathetic” to the argument that anyone has a right to own a gun.

This all feeds into the argument that my coauthor Ken Blackwell and I raise in our bestseller The Blueprint: Obama’s Plan to Subvert the Constitution and Build an Imperial Presidency, that President Obama is advancing a gun-control agenda by packing the Supreme Court with justices who will hold that the Second Amendment means nothing at all. (In The Blueprint, we also predicted Kagan as a likely Obama pick).

Republican senators must therefore press Elena Kagan on this issue. They should also be unrelenting–using every tool at their disposal–not to allow her nomination to progress until they’ve had the opportunity to thoroughly review all Clinton White House documents involving Kagan’s views on gun rights. If she was indeed “immersed” in that issue, then there’s a good chance that one of those documents reveal her personal views on the Second Amendment.