Something just doesn't add up...
The problem is that the harder one looks at the allegations about Manour Ababasiar, the fishier the whole business seems. There's no question that Iran has relied upon assassination as a foreign policy tool in the past, but it boggles the mind to imagine that they would use someone as unreliable and possibly unhinged as Ababsiar. I won't rehash the many questions that can and should be raised about this whole business; for compelling skeptical dissections, see Glenn Greenwald, Juan Cole, Tony Karon, and John Glaser.
As I said yesterday, I don't know what actually happened here, and I remain open to the possibility that there really was some sort of officially-sanctioned Iranian plot to assassinate foreign ambassadors here on U.S. soil. But the more I think about it, the less plausible whole thing appears. In particular, blowing up buildings in the United States is an act of war, and history shows that the United States is not exactly restrained when it responds to direct attacks on U.S. soil. Japan attacked Pearl Harbor and we eventually firebombed many Japanese cities and dropped two atomic bombs on them. Al Qaeda destroyed the World Trade Center and damaged the Pentagon, and we went out and invaded not one but two countries in response. When it comes to hitting back, in short, we tend to do so with enthusiasm.
Hence the growing skepticism, including the possibility that this might be some sort of "false flag" operation by whatever groups or countries might benefit from further deterioration in U.S.-Iranian relations. If the Obama administration can't back up their allegations in a convincing way, they are going to face a diplomatic backlash and they are going to look like the Keystone Cops. They could even face a situation where rightwing war-mongers seize on their initial accusations to clamor for harsh action (a development that has already begun), while moderates at home and abroad lose confidence in the administration's competence, credibility, and basic honesty.