Q&A: Supreme Court gun law decision
What are the implications of the US Supreme Court's decision to say that the Second Amendment right to bear arms applies across the whole of the country?
What prompted this ruling?
The case was brought by four residents in Chicago, Illinois, who wanted the right to have handguns, as well as local firearms activists and the National Rifle Association (NRA).
In Chicago, as well as its suburb of Oak Park, there is effectively a ban on handguns for most people because of the difficulty in registering a weapon.
Two years ago the Supreme Court ruled that Washington DC's ban on handguns was unconstitutional and this case soon followed.
What's wrong with Chicago's law?
The Second Amendment of the US Constitution, as ratified by Congress, says: "A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
There have long been arguments about whether and what weapons are allowed under the amendment.
Proponents of gun control say the constitution's provisions are entirely about the maintenance of a militia.
Opponents of gun control say the right to have a weapon is clearly enshrined.
In the latest ruling, the Supreme Court justices said the Second Amendment right "applies equally to the federal government and the states".
The court's decision does not explicitly strike down the Chicago area laws, but it requires a federal appeals court to reconsider its ruling.
So does this mean that the US will soon have just one law on guns?
No. The US currently has a patchwork of gun control laws. In many places it is reasonably easy to have a handgun in the home, but the situation as regards carrying a gun in public differs from state to state and even county to county.
There are places where a licence to carry a concealed firearm is on a "shall issue" basis - the authorities must have a reason to turn down an applicant, for example that they are mentally ill or a criminal. In other places, the onus is on the applicant to justify that they need to carry a weapon.
Many state legislatures may now look at their law to see if it corresponds to the ruling, but the Supreme Court has set out no universal template. Many states' laws will be defined in what is likely to be a series of future legal battles.
Why is the issue important?
To advocates of gun control, tight legislation is a way to fight crime and reduce gun death rates. To opponents, not only is bearing arms constitutionally guaranteed, but it is an important part of a person's right to defend himself against criminals.