Editorial: Once again, the US reels from classified data leaks. This time, Ukraine’s at stake

The gaping holes that Chelsea Manning and Edward Snowden poked into what America assumed were secure, firewalled troves of classified data taught Washington a sobering lesson about the importance of keeping secrets leakproof.

Now, however, it seems Washington needs a refresher course.

The Pentagon is scrambling to find the source responsible for a tranche of leaked documents, the release of which reveals timely information that could severely compromise Ukraine’s bid to defeat Russian forces. The task of tracking down the culprit or