From the NYT:

"Today the Supreme Court will hear arguments in a politically charged challenge to the District of Columbia’s gun control laws. The case poses a vital question: can cities impose reasonable controls on guns to protect their citizens? The court should rule that they can."

From the Bill of Rights:

"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."

From my perspective, its pretty clear that guns in cities are not tied to militia service. Therefore, reasonable limits are acceptable.