FACTBOX: U.S. presidential candidates and gun control

(Reuters) - Following are the positions of the leading U.S. presidential candidates on gun control.

DEMOCRATS

SEN. HILLARY CLINTON

She has said law-abiding citizens should be able to own guns but laws are needed to keep guns out of the hands of criminals. She co-sponsored legislation to reinstate for 10 years a ban on assault weapons.

The National Rifle Association gives her a failing grade of F for her position on guns.

SEN. BARACK OBAMA

Wants tighter background checks on gun buyers, making gun locks mandatory and holding parents criminally responsible for children who injure someone with a gun found at home. Supports reinstating assault-weapons ban.

The National Rifle Association gives him a failing grade of F for his position on guns.

REPUBLICAN

SEN. JOHN McCAIN

Opposes gun control, calling it "a proven failure in fighting crime." Opposes waiting periods to buy firearms. Has supported legislation requiring gun makers to include trigger locks with their products. Opposes reinstating assault-weapons ban. Has supported mandating background checks on gun buyers at gun shows.

The National Rifle Association gives him an average grade of C for his position on guns but says he has a perfect voting record since 2007 and his grade may be revised.

Sources: Reuters, campaign Web sites, Detroit Free Press, the National Rifle Association

(Compiled by Paul Grant, Washington Editorial Reference Unit)