Bret Stephens: Trump is locked, half-cocked and probably bluffing

Thomas Jefferson warned against entangling alliances. John F. Kennedy was ready to pay any price and bear any burden. Teddy Roosevelt advised us to speak softly and carry a big stick.

And then there’s Donald Trump. Locked, half-cocked, and probably bluffing.

That’s the lesson Iran’s leaders appear to have drawn following a carefully calibrated sequence of escalatory attacks against the U.S. and its allies in recent months.

In May, there were four unclaimed attacks on tankers transiting near the Strait of Hormuz — two Saudi, one Norwegian, and one Emirati. In June, two more tankers were attacked, and U.S. surveillance video caught an Iranian patrol boat in close vicinity to one of the damaged…