Tuesday's session was a bloodbath for everything with a chip in it. The Nasdaq Composite cratered 2.5% at the opening bell as a global tech rout that started overnight in Seoul washed onto Wall Street. South Korea's KOSPI crashed 10% — its worst session in years — after memory giants Samsung Electronics and SK Hynix got obliterated. The S&P 500 shed roughly 1%, though the Dow's old-economy tilt kept the blue-chip index in better...