One of the many fascinating items from the "Photography and the American Civil War," exhibit at the Met was the faulty Union intelligence McClellan relied on, and probably exaggerated, to believe Lee had many more troops than in fact he did at Antietam. This was a justification by McClellan for the caution he showed in a battle where he vastly outnumbered Lee.
I don't know why Intelligence assessments seemingly have such a talismanic impact on policy makers, given their long history of being spectacularly wrong. That is certainly unfair characterization since I have no knowledge of all the times the Intel has been right.
But it seems to me President Obama wanting to be sure of intelligence assessments before taking action in Syria is a good idea.
On that front the most amusing comments come from Obama's supporters, like Cokie Roberts on This week. It is really a shame, she says, we invaded Iraq and Afghanistan because now the American people are antagonistic to wars in the Middle East, limiting Obama's ability to project power. An alternate version of that complaint is "Damn George bush for going to war, because now Obama can't." Cokie Roberts and the knee jerk supporters of Obama are always good for a laugh.