Aside from the fact that Persians tend to look more European than Arabs, and speak a different language, and associate with pro-Iranian groups like the Mahdi Army instead of al-Qa'ida in Iraq, you mean?
The actually intelligence that rolls in on these guys either comes from Iraqis that know the difference, linguists that speak Farsi, and other sources identifying sources. The average Joe doesn't need to get the Arab/Persian problem right, just the intelligence guys spotting the targets.
Being familiar to Middle Eastern people I for example could easily spot the difference between an Arab and a Persian. As already said Persians look more Caucasian/European... like Italians or Greek.
Note that not all Iranians are Persians, who only are 45-50 % of Iran's population. 20% are Azeris, who are related to Turks. Many leading clerics are Azeris (including Khameini).
Then there are Iranian Kurds, Arabs, Turkomen, Armenians, Baluchis, Loors, etc. etc.
I would suspect that Iran's agents in Iraq are mostly Arab Iranians from the Southern Khuzestan Province, or Shia Arabs from Lebanon/Iraq trained for decades in Iran.
Nonsense. I have lived in Iran and Saudi Arabia. You would have a a very difficult time differenting among the two based on physical appearance [discounting their clothing].
It is also worth noting that almost half of the country's population is not Persian. Of these non-Persians, the Kurds alone account for some 9 percent of Iran's population, and their national sentiments have certainly been strengthened by the example of virtual Kurdish independence in Iraq next door. As their demands for cultural autonomy become more forceful, something of an insurgency seems to have started in Kurdish-inhabited parts of northwestern Iran. Smaller nationalities, too, have recently engaged in acts of violent resistance, including the Arabs at 3 percent of Iran’s population and the Baluch of the southeast at 2 percent.
Taken together, the Kurds, the Arabs, the Baluch, plus several other ethnicities (Turkmen, Lurs, Gilaki, and Mazandarani), whether in any way dissident or not, amount to a quarter of Iran’' population. But another quarter at least is added by the Turkish-speaking Azeris. Although many Azeris, especially in Tehran, are thoroughly assimilated, many others increasingly affirm their Turkic national identity, and groups calling for cultural autonomy or even separation have become increasingly active among them. Ever since Azerbaijan, just across the border, gained its independence from the Soviet Union, the Azeris have had a national home of their own, and it is not Iran.
Thanks, again, for providing a serious answer to a serious question.
When I was in Germany in 1967* I travelled around with a Jewish girl from New Jersey. She was taken aback by the way German students asked her, "Are you Persian?" .
*the days of anti-Shah student uprisings in Germany
Benno Ohnesorg (October 15, 1940 - June 2, 1967) was a German university student killed by a police officer on June 2, 1967, during a demonstration in Berlin against the visit of the Shah of Iran, Mohammad Reza Pahlavi, to Germany. It was the first political demonstration that the married student (of Romance and German literature and culture studies) attended as part of the German student movement.His death served as a rallying point for the radical left wing, and the Movement 2 June group was named after the day of his death. The left-wing student movement of the late 1960s that swelled after Benno Ohnesorg's death influenced a large number of German politicians who were in their teens and twenties at the time. It has been viewed by many as the second-most influential and important event in Germany during the period of East and West Germany, second only to the construction of the Berlin Wall. ...