President Donald Trump and his administration have every right to make a case to reduce the threat of terrorism by tightening procedures for allowing foreigners into the United States, and then to implement those new steps carefully and fairly. That’s not what happened this weekend, when Trump only inflamed an already stressful situation.

His executive order to stop refugees and people from predominantly Muslim countries from entering the United States is confusing, arbitrary and overreaching. It was enforced hastily and likely illegally, creating chaos at airports worldwide and sparking nationwide protests. It bypassed processes necessary for the effective functioning of government.

It also achieved an unintended irony: A president and administration that have made the country’s safety a top priority might have accomplished the opposite. The biggest consequence of this fiasco is not what happened to the 200 or so people detained at U.S. airports, or the greater number left in limbo overseas. It’s how the rest of the world now looks at America.

What are others to think when the new policy ensnares a doctor in a residency program at the renowned Cleveland Clinic? An interpreter who worked for the U.S. military in Iraq for more than 10 years? A PhD student in linguistics at Stony Brook University? Husband-and-wife green-card holders, both disabled, ages 88 and 83?

The potential damage is far-reaching. Our military personnel in dangerous places overseas are more at risk of not getting cooperation from local residents. International business and critical research at American universities are threatened. This bungled exercise, an expression of intolerance, is a calling card for Islamic State recruitment. And worries about homegrown terrorists harboring grudges about America’s treatment of Muslims are now only heightened.

Denying entry to people with valid visas when they started their travel likely is illegal. A blanket ban of green-card holders returning to the country, or submitting them to extra scrutiny without probable cause, is flat out wrong. All day Sunday, the White House struggled to tamp down criticism and finally seemed to back off that directive.

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Trump and chief strategist Stephen Bannon have been so focused on the bulldozer optics of their first 100 days that they have ignored critical processes. In this case, they reportedly bypassed at least three departments — Justice, State and Homeland Security — and did not notify our allies, creating unnecessary havoc and harm.

Trump is right to want to make it difficult for terrorists to enter the country. But he denies reality when he says it is easy for refugees to come here. The vetting process already involves multiple agencies and takes up to two years. Permission once granted cannot be arbitrarily snatched away. That betrays our procedures and our ideals. Trump would be wise to surround himself with fewer ideologues and more people who understand the process of governing.

Ohio GOP Sen. Rob Portman got it right when he said this extreme vetting proposal was not well-vetted, and that Congress and agency heads should be involved. Trump has to get this right.

Sometimes in trying to shock the system, you end up harming yourself as well. — The editorial board