Reporter's Notebook: Congressional Republicans stand by Trump on Iran military action despite campaign promise

Sir Isaac Newton postulated that for every action, there is always an equal and opposite reaction. It’s Newton’s Third Law of Motion and one of the most important rules in all of science.

And Newtonian physics can tell you a great deal about reactions in politics.

We don’t yet know the dimension or the impact of the war in Iran. But there will be a political reaction of great importance as we head toward the midterms. It’s just too early to understand how the war will go, what unexpected...