A group of influential senators rolled out a sweeping bill to overhaul the nation’s criminal justice system and sentencing laws, reviving a bipartisan effort that had been left for dead last year. The new legislation, led by Sens. Chuck Grassley (R-Iowa) and Dick Durbin (D-Ill.), is aimed at easing sentences for some non-violent offenders, such as for drug crimes, while beefing up other tough-on-crime laws.