* Five critical rules of gun safety from the NRA and other sources:

1) Always keep the gun pointed in a safe direction (whether loaded or unloaded).

2) Always keep your finger off the trigger until ready to shoot.

3) Always keep the gun unloaded until ready to shoot.

4) Be aware of what is behind your target.

5) When handling firearms, never use alcohol or any drug that might impair your awareness or judgment (including prescription drugs).[134]

* The President of the United States appoints judges to the Supreme Court. These appointments must be approved by a majority of the Senate.[143] Senate rules allow for a "filibuster," in which a vote to approve a judge can be blocked unless unless three-fifths of the senators (typically 60 out of 100) agree to let it take place.[144] [145]

* Once seated, federal judges serve for life unless they voluntarily resign or are removed through impeachment, which requires a majority vote of the House of Representatives and a two-thirds vote in the Senate.[146]

* On June 26, 2008, the U.S. Supreme Court, in a 5-4 decision, ruled that Washington's D.C.'s handgun ban was unconstitutional.[147] Both of the Justices appointed by Democrats voted to uphold the ban, and five of the seven Justices appointed by Republicans voted to strike it down.[148]

* Of the five Justices who voted to strike down the D.C. handgun ban, Barack Obama voted against the nomination of two of them and identified two of the others as judges he would not have nominated.[149] [150] [151] Of the four justices who voted to uphold the handgun ban, John McCain identified all of them as judges he would not have nominated.[152]

* In May 2009, President Obama announced Sonya Sotomayor as his first nominee to the Supreme Court.[153] She was confirmed in a 68-31 Senate vote, with 100% of Democrats voting for her confirmation and 78% of Republicans voting against it.[154]

* Within a year of being confirmed to the Supreme Court,[155] Sotomayor joined in a dissenting opinion declaring that Chicago's handgun ban was constitutional, that "the use of arms for private self-defense does not warrant federal constitutional protection from state regulation," and that the Framers of the Constitution "did not write the Second Amendment in order to protect a private right of armed self-defense."[156]

* In May 2010, Obama announced his second nominee to the Supreme Court, Elena Kagan.[157] As a law clerk for Supreme Court Justice Thurgood Marshall, Kagan wrote a memo recommending Marshall deny hearing an appeal from a man who was convicted of violating Washington, D.C.'s gun laws. She wrote in the memo:

[The man's] sole contention is that the District of Columbia's firearms statutes violate his constitutional right to "keep and bear arms." I'm not sympathetic.[158]

* Kagan was confirmed to the Supreme Court by the Senate in a 63-37 vote, with 98% of Democrats voting for her confirmation and 88% of Republicans voting against it.[159]