PEGGY NOONAN: The Travel Ban And The New Czar.

What normal people can see and imagine is that three Ebola cases have severely stressed the system. Washington is scrambling, the Centers for Disease Control is embarrassed, local hospitals are rushing to learn protocols and get in all necessary equipment. Nurses groups and unions have been enraged, the public alarmed—and all this after only three cases.

What would it look like if there were 300? That is not a big number in a nation of over 300 million. Yet it would leave the system hyperstressed, and hyperstressed things break down.

How many people and professionals have been involved in the treatment, transport, tracking, monitoring, isolation and public-information aspects of the three people who became sick? Again, what if it were 300—could we fully track, treat and handle all those cases? If scores of people begin over the next few weeks going to hospital emergency rooms with Ebola, how many of their doctors, nurses, orderlies, office staffers, communications workers and technicians would continue to report to their jobs? All of them at first, then most of them. But as things became more ragged, pressured and dangerous, would they continue?

This is why people are concerned. They can imagine how all this could turn south so fast, with only a few hundred cases. This is why the White House claims that we will not have a widespread breakout is fatuous: Even a limited breakout would take us into uncharted territory.

The only thing that will calm the public is competence.

Uh oh.