[Siira]

This is a lie. The chant is literally "Death to X," there is no idiom whatsoever. The only human targets I have ever heard for this chant is the US and some of its allies (KSA, UK), the IR's leader, and some generic terms for the outgroup ("monafegh").

[EB-Barrington]

This should may help you, and other interested persons determine whether or not marg bar Amrika is to be taken literally, or is indeed an idiom (btw, it is):

In Persian, "Death to America" is "marg bar Amrika"

Common Persian phrases, and these are everyday phrases in Iran include:

1) Marg! Literally, Death!, closest we have in English: Shut up!

2) Khabare margesh! Literally, the news of his/her death! This is used with someone you don't like, as in, you're only interested in the news of that persons death (perhaps a politician is a typical example).

3) Boro bemir! Literally, Go die! Again, in English, the equivalent is along the lines of Shut Up!

4) Che margeshe? Literally, what's his death? Used mostly for objects, such as when your car won't start.

5) Marge man, literally, my death. Used when you are swearing you are telling the truth.

Iranians have so many idioms/expressions/figures-of-speech related to Death, this is just a small sample.

[miracle2k]

During the protests last year, Sohrab Ahmari, no friend of the IRI, chose to translate the phrase as "Down with the dictator". I wonder why.