Stock futures are flat following big sell-off as Trump’s tariffs spark retaliation: Live updates

U.S. stock futures were flat Tuesday after a big sell-off on Wall Street, as President Donald Trump's tariffs on Canada, Mexico and China took effect. Futures tied to the Dow Jones Industrial Average slipped 57 points, or 0.1%. S&P 500 futures lost 0.1%, and Nasdaq 100 futures were marginally…