Kim Strassel for The Wall Street Journal, here:
Nothing Mrs. Clinton has supplied to the State Department can now be trusted as legitimate. The real bombshell news was the State Department’s admission that, in at least six instances, the Clinton team altered the emails before handing them over. Sentences or entire paragraphs—which, by the way, were work-related—were removed. State was able to confirm this because it could double-check against Mr. Blumenthal’s documents.