Balloons and national security: What we know so far

The U.S. military’s unprecedented destruction of four objects floating through the upper reaches of North America’s atmosphere raises a difficult question: Is this stuff benign, or a genuine national security problem in the making?

From what we know now, the answer may be “both.” Current evidence released about the events of recent days has revealed a mixed picture. U.S. officials remain adamant that the first object was a large, sophisticated spy balloon from China. They have been careful to put the others in a different category, referring to them as smaller, less sophisticated devices traveling on lower-level winds.

But the spy balloon by itself remains a troubling portent for the Pentagon and U.S. defense overall, say some lawmakers,