The gruesome images are clear. There's little doubt Syrians suffered a chemical attack last month. But videos of the aftermath -- including 13 shown to Congress -- do nothing to show who was responsible. President Barack Obama says he has high confidence that the regime is to blame -- the strongest position short of confirmation. But his administration has not released hard evidence. Secretary of State John Kerry says declassifying any more information could endanger sources and methods of U.S. intelligence gathering. Britain, France and NATO also blame Syrian President Bashar al-Assad for the horror in a Damascus suburb last month. Still, as Obama engages in a full-court press to build U.S. support for strikes, some Americans hear echoes of a different basketball analogy: slam dunk. That's how then-CIA Director George Tenet described what turned out to be flawed intelligence that Iraq had weapons of mass destruction in the run-up to the war 10 years ago. Kerry and Defense Secretary Chuck Hagel were senators at the time. We are especially sensitive, Chuck and I, to never again asking any member of Congress to take a vote on faulty intelligence. And that is why our intelligence community has scrubbed and re-scrubbed the evidence, Kerry told Congress. Some lawmakers remain skeptical. The administration is asking us to go to war on the basis of a four-page document and a