WASHINGTON — For three years, President Trump’s critics have expressed concern over how he would handle a genuine international crisis, warning that a commander in chief known for impulsive action might overreach with dangerous consequences. In the angry and frenzied aftermath of the American drone strike that killed Iran’s top general, with vows of revenge hanging in the air, Mr. Trump confronts a decisive moment that will test whether those critics were right or whether they misjudged him...... In scrambling the equation, Mr. Trump took the initiative, not as Mr. Bush or Mr. Obama did in their own very different...