court green light a massive discrimination lawsuit against walmart? arguments today in one of the most important workers' rights cases the court has ever heard. i'm wolf blitzer. you're in "the situation room." moammar gadhafi and his troops are being accused of new carnage and destruction. just hours after president obama tried to explain the u.s. mission in libya to the american people. this hour we have breaking news. we're learning about major, major setbacks for rebel forces in several cities. in misrata, witnesses say government forces are hammering the city hard, firing bullets over civilians' heads and telling them to run for their lives. gadhafi is fighting back with a vengeance against rebels who had regained ground in recent days under the cover of coalition air strikes. and joining us now in ajdabiya is our own arwa damon. you're with the rebels there.