Lol.. Someone has filled your head with all sorts of bullshit it isn't even funny.
First, no- the foreign minister of Iran does not know the US constitution (and it's definition of treason and the laws passed based on that definition) better than the republicans in the Senate do. The president can only enter into a treaty if the senate consents. This is elementary school civics. The administration can come to some executive agreement, but any future administration can nullify it at will because it is not a treaty. What the foreign minister referenced was a misinterpretation of international law which has a principle that agreements between the head of state are treated treaties in dispute resolution. However, this is not binding to the US because we are both not members of the international court of justice and we have an established process declaring what a valid treaty is.
Second, the treason crap you spewed is wrong on so many levels. First, treason is specifically defined by the Constitution so violations of the Logan act (a law) which do not involve levying war against the united states, or in adhering to their enemies, giving them aid and comfort. will not be treason by any stretch of the imagination. Second, the logan act specifically involves unauthorized persons which members of the government are authorized. Further, the advice and consent portions of the constitution imply the senate has a specific right to give advice in foreign relations.
The sole reason no one is not being prosecuted for the letter is because violations of the law only exist in partisan political minds and not in reality or matters of law. Several of the president's strongest detractors could be taken out in one swoop if they were prosecuted for this but the justice department knows any attempts to prosecute will fail.
So are you surprized when Republican voters who shout constitution all the time turn out to have no idea what is in it or what it means ? Of course not, the senators they elect don't even know it !
I'm simply amazed at how ignorant people are about the constitution. Do they not teach this in school any more? When I was in school, we had government and civics coursed in a couple of different years (starting in 8th grade) and the last two runs (11th and 12th grades) were actually requirements to graduate.