Additional Diplomacy=
To: Iran
From: Empire of Japan
We apologise for the unfortunate use of the word vassal, but to all intents and purposes it is true.
Iran is held by the US in vassalage. We mean no offence by it it is simply a statement of fact.
You are definately vassals, for the US use your based, have troops based in Iran, and basically dictate Irans foreign policy. Again we mean no offence, we just state it as we see it.