Senate Majority Leader Mitch McConnell's reluctance to hold a vote on a popular criminal justice bill is angering some Republican senators and creating an unusual rift with a longtime ally, Chuck Grassley of Iowa.

Grassley has spent years working to build a coalition around the bill. The Judiciary Committee chairman is pushing for a year-end vote and has support from President Donald Trump. But McConnell says it's too divisive, and he's refusing to bring the legislation forward.

The legislation would reduce mandatory sentences for some drug crimes. But opponents say it would allow some dangerous criminals to leave federal prison earlier.

Now there's talk of attaching the justice reforms to a year-end spending bill that's needed to keep government running. Senators want to avoid a partial shutdown days before Christmas.