WASHINGTON (AP) — More than two-thirds of state attorneys general now back the right of reporters to withhold the identity of their sources in most federal court cases.

The Newspaper Association of America said Thursday that 37 attorneys general have signed a letter to Senate leaders in support of a media shield bill.

"By affording some degree of protection against the compelled disclosure of a reporter's confidential sources, these state laws advance a public policy favoring the free flow of information to the public," the attorneys general wrote to Senate Majority Leader Harry Reid, D-Nev., and Minority Leader Mitch McConnell, R-Ky.

A media shield bill won passage overwhelmingly in the House in October, after a similar measure cleared the Senate Judiciary Committee.

Yet it faces an uncertain future in the Senate, where there is strong opposition from some Republicans. The White House has threatened to veto the legislation, arguing it would encourage leaks of classified information.