...In an interview with me earlier this week, she used her sharpest language yet to describe the "failure" that resulted from the decision to keep the U.S. on the sidelines during the first phase of the Syrian uprising.

“The failure to help build up a credible fighting force of the people who were the originators of the protests against Assad—there were Islamists, there were secularists, there was everything in the middle—the failure to do that left a big vacuum, which the jihadists have now filled,” Clinton said.

As she writes in her memoir of her State Department years, Hard Choices, she was an inside-the-administration advocate of doing more to help the Syrian rebellion. Now, her supporters argue, her position has been vindicated by recent events....