Editor's note: Jeffrey Toobin is a senior legal analyst for CNN and a staff writer at The New Yorker magazine, where he covers legal affairs.
(CNN) -- The case against Manssor Arbabsiar, the Iranian-American charged with conspiring to assassinate the Saudi Arabian ambassador to the United States, looks like a dazzling mix of high drama and low comedy, high stakes and low dealing. The prosecution has enormous implications for the United States' relationship with Iran -- and thus for world peace -- but it's also a criminal case in an American courtroom. So it's worth asking: how strong is that case?
Of course, United States v. Arbabsiar has just begun, and so far we've only heard the government's side of the story. But enough information is out there to at least start asking some educated questions about how the case might unfold.
For starters, there is the issue of "CS-1," who appears to be the critical government witness in the case. The prosecution seems based in a significant amount on the Confidential Source, who met repeatedly with Arbabsiar and taped conversations with him. But who is he? According to the complaint, filed in New York federal court Tuesday, "CS-1 is a paid confidential source. Previously, CS-1 was charged in connection with a narcotics offense by authorities of a certain U.S. state. In exchange for CS-1's cooperation in various narcotics investigations, the State charges were dismissed."
It's the kind of description that sets a defense attorney to salivating. The argument for the defense might go like this: "CS-1 -- a crafty and duplicitous drug dealer -- knew he had to land a big fish to work off his beef. So CS-1, not Arbabsiar, concocted this ludicrous scheme to enlist Mexican drug cartels in an assassination on American soil. Jurors should be outraged that the American government is lining up with, and paying American taxpayer dollars to, a crook like him." And even according to the complaint, it was CS-1 (not Arbabsiar) who came up with the much-ballyhooed figure of $1.5 million as the price to the Iranians for the killing.
Of course, there are many potential responses to this kind of argument. For starters, according to the complaint, the tapes reveal that Arbabsiar was an enthusiastic participant in the scheme, goading CS-1 to pursue the hit, not the other way around. And Arbabsiar also apparently arranged for the down payment of almost $50,000 to be wired to CS-1. And perhaps most important, following his arrest, again according to the complaint, Arbabsiar "confirmed that he agreed to pay CS-1 to kill the ambassador." Those will be tough facts for the defense to refute, but an unsavory informant at least gives the defense a target for blame.
The interrogation of Arbabsiar is another subject the defense will want to explore. Recent reports suggest that Arbabsiar may have been questioned for as long as 12 days, and by Mexican as well as American officials. Investigations of this kind present dicey challenges for the American authorities. Above all, U.S. officials want to protect our national security and identify and prevent possible terrorist attacks. The point here is to get information from the suspect and not worry about such niceties as Miranda warnings. National security will always trump law enforcement.
But a criminal prosecution operates by very different rules. Miranda warnings are required for suspects in custody, and their statements can be suppressed if there was no Miranda, or some kind of coercion. The potential involvement of Mexican officials (not known for their delicate treatment of suspects) raises other questions. Again, it's possible, even likely, that these issues will be resolved in the government's favor, but the pretrial proceedings are likely to be complicated and lengthy.
Another complexity: Arbabsiar will likely ask for extensive discovery from prosecutors, including all wiretaps and intercepts where he was recorded or mentioned. It's common knowledge that the National Security Agency engages in extensive surveillance of Iran, and Arbabsiar will seek all of NSA's files on him and everyone mentioned in the case. But NSA (nickname: No Such Agency) is famously protective of its secrets and will want to disclose as few as possible to a criminal defendant, much less a suspected terrorist. A law called the Classified Information Procedures Act (CIPA) is designed to allow federal judges to sort out these kinds of issues in advance of trial, but again, these hearings tend to be complicated and time-consuming.
In all, then, the case against Arbabsiar may well be airtight. Certainly, this fellow is in a world of trouble, and in the end, he may even decide to plead guilty and become an informant himself. But Arbabsiar may well fight to the end. Cases only become more complicated over time, and there's every reason to think that this one will, too. The case arrived with great and surprising suddenness, but it may now be a long slog to a jury verdict and beyond.
The opinions in this commentary are solely those of Jeffrey Toobin.