The pundits are right. The vindictive traffic-lane shutdown was a gift to Mrs. Clinton—but not for the reasons generally supposed. The brouhaha about Mr. Christie did her a major favor by overshadowing news that had just broken about a forthcoming memoir by former Defense Secretary Robert Gates, which relates an episode about Mrs. Clinton that ought to alarm even her most ardent supporters.

Just to review: Mr. Gates served in President Obama’s cabinet alongside Mrs. Clinton when she was secretary of state. In his book, Mr. Gates recalls that in a 2009 discussion about President George W. Bush’s decision to commit more troops to Iraq, Mrs. Clinton “told the president that her opposition to the [2007] surge in Iraq had been political because she was facing him in the Iowa primary.” President Obama then “conceded vaguely” that he opposed the surge for similar reasons.