Four lawmakers, including one presidential hopeful, want the Entertainment Software Ratings Board to review the rating system for video games since Manhunt 2 received an "M" for mature.

Senators Joe Lieberman (I-Conn.), Sam Brownback (R-Kan.), Evan Bayh (D-Ind.), and Hillary Rodham Clinton (D-N.Y.) sent a letter to the board this week, saying that Manhunt 2's rating had "opened the door to widespread release of the game, which depicts acts of horrific violence."

Rockstar representatives have argued in favor of free expression and likened the fears about video games to protests over various art forms, including rock music.

In June, the British Board of Film Classification refused to rate Rockstar's Manhunt 2 video game, effectively banning its sale in British stores. The British board said the game has an "unremitting bleakness and callousness of tone ... which constantly encourages visceral killing with exceptionally little alleviation or distancing."

The British board said that any other action "would involve a range of unjustifiable harm risks, to both adults and minors." In October, it refused to rate a revised version of Manhunt 2, stating that "there has been a reduction in the visual detail in some of the 'execution kills', but in others they retain their original visceral and casually sadistic nature."

The American ratings board originally rated the game "AO" for adults only. However, it changed the rating to "M" after the game was revised, allowing widespread distribution and licensing approval by Sony, Nintendo, and other game manufacturers.

"While significant progress has been made, the FTC reports that 42% of unaccompanied children 13 to 16 years of age can still successfully purchase M-rated games meaning that the practical difference between an AO and M rating affects more than simply 17-year-olds," the Senators said in the letter.

On Nintendo's Wii system, Manhunt 2 players can act out torture scenes and murders instead of pressing buttons or moving joysticks on traditional remote controls. "This led one clinical psychologist to state that the realistic motions used with the Wii mean that 'you're basically teaching a child the behavioral sequencing of killing," the Senators pointed out.

They said the American ratings board should take the Wii remote controller, and other advances in game controllers, which create more realistic gaming environments, into consideration in their ratings system.

The AO version was leaked through the Internet, reportedly by a Sony employee who was fired. "The possible use of the Internet to circumvent the ESRB and permit broad access to kids is another concern," the letter states.

The letter calls on the board to explain why it does not fully inform the public and developers about the reasons for rating changes, even after games have been released. It also asks whether those who provide the original ratings also rate revised versions of games, how frequently the board uses more than its minimum of three reviewers, and whether three reviewers is sufficient. Finally, the lawmakers want to know how often reviewers disagree over the ratings and how frequently ratings are a result of majority opinion, rather than consensus.