Donald Trump's victory in the 2016 U.S. presidential election defied long odds and the widespread assumption that Hillary Clinton had the contest in the bag. That experience led many to suspect that — no matter how big Joe Biden's lead is this time — it's inevitable that Trump will prove the polls wrong again. That's a possibility, of course. But a lot has changed since 2016. The CBC's Presidential Poll Tracker gave Clinton a 3.4-point lead in national polls over Trump on election day. She was projected to win North Carolina and Florida by narrow margins, with Michigan, Pennsylvania and...