President Biden told business leaders Wednesday that former President Donald Trump is an “existential threat” during a three-stop fundraising tour of New York City that was beset by anti-Israel protesters who blocked Fifth Avenue outside the Metropolitan Museum of Art. “There is one existential threat: it’s Donald Trump‚” the 81-year-old president said at his first stop of the day — an environment-focused afternoon gathering at the Upper West Side home of Larry Linden‚ the former...