We are not in World War III. Trump called for peace and a ceasefire between Iran and Israel. He set back Iran’s nuclear and missile programs through strong action. After Iran fired missiles at the Al Asad Airbase in Iraq, he responded by calling for peace. He handled the situation well which is shown by the strong stock market and lower gas prices, which suggest most Americans aren’t worried about how this will pan out.
Soleimani was leading plans for attacks on U.S. diplomats and military bases, which could have caused many American deaths. If Trump hadn’t acted, Iran might have launched missiles at the U.S. itself. By removing Soleimani, the U.S. stopped those attacks before they happened and slowed Iran’s ability to develop more powerful missiles.