National Headlines 12-21-15

Will the GOP Mount a Third-Party Challenge to Trump? (Politico)

Clinton campaign sweats out data breach damage (Politico)

Sanders’s suit against DNC still alive in federal court (The Hill)

Congressional leaders gear up for broad tax reform push (The Hill)

What really happened to the U.S. train-and-equip program in Syria? (McClatchy)

Democratic Committee digs deeper in opposition research (New York Times)

Lindsey Graham suspends his presidential campaign (Washington Post)

Obama: Trump is ‘exploiting’ anger and fear over economic insecurities (Washington Post)

California shooters’ ex-neighbor denied bail in terrorism case (Reuters)

Hillary Clinton camp to Donald Trump: ‘Hell no’ on apology (CNN)

Former official: Iranians hacked into New York dam (CNN)