Democratic leader Schumer emerges as Trump's newest punching bag

By Richard Cowan WASHINGTON (Reuters) - President-elect Donald Trump, who insulted rivals during his 2016 campaign with nicknames such as "Crooked Hillary" and "Little Marco," has a new nemesis: U.S. Senate Democratic leader Chuck Schumer, a man he derides as a "clown." The rhetorical banter that erupted between the two New Yorkers this week centered on a fight over Republican plans to dismantle Obamacare, an effort that Trump has put at the top of his domestic agenda. Just two weeks before he i