"Leaked" by the Obama Administration as a message to the Chinese.
Not a bad move on Obama's part. For once, a slight hint of strategery, as long as they don't call his bluff.
They probably have no idea that he's a sniveling whinging empty suit. jk
I suspect all of the Guardian and Washington Post leaks are all from one person, essentially a Bradley Manning with a higher clearance.
Given the much more limited distribution of the TS material being leaked, they’re going to find the source fairly quickly
The source certainly knows this, per an interview with the Washington Post reporter.