Two weeks ago I wrote a column titled “The Stock Market Isn’t Convinced Trump Is Serious About Tariffs.” I argued in the piece that investors were acting like the president was bluffing. The S&P 500 had just hit a record high, volatility was low, and no one blinked when Trump signed off on reciprocal tariffs. That was then.

The major U.S. stock indexes opened lower on Tuesday, as President Trump's tariffs went into effect. The tariffs against Mexico, Canada and China were initially delayed a month to give these countries the opportunity to negotiate,