NEW : Obama says no law can stop all gun violence , but the nation must try . NEW : Obama continues to call for reviving a ban on some weapons . New : Obama calls for universal background checks and an assault weapon ban. The focus on gun control is revived after the Connecticut school massacre .
NEW : Obama says no law can stop all gun violence , but the nation must try . NEW : Obama continues to call for reviving a ban on some weapons . A Senate leader questions if a weapons ban will be part of a legislative package . The focus on gun control is revived after the Connecticut school massacre .