Hillary Clinton’s Brussels response was basically boilerplate, calling for solidarity with Europe and playing chess with Trump to paint him as a greenhorn and hothead. Bernie Sanders (whom I support and contribute to) had little to say, beyond conveying condolences to the Belgian people, because foreign affairs have unfortunately remained a sideline for him. Neither Sanders nor Martin O’Malley ever went after Hillary’s disastrous record as Secretary of State with the tenacity that they should have—a failure of strategy that has proved costly in the long run. Trump may be raw, crude and uninformed, but he’s also smart, intuitive and...