Imagine Thai, Chinese and Russian diplomats seek to be present at Edward Snowden interrogation. Imagine what America will say if that happens. That forms the core of the current uproar within one side of the Thai political divide against what was perceived as western diplomats “crossing the line” in the increasingly controversial Thanathorn case.

The Thai, Chinese and Russian diplomats will not ask to be present, let alone going ahead and being there, say the critics, who believe they are backed up by the Vienna Convention which governs diplomatic protocols when it comes to “national security” cases in the third country.

Prime Minister Prayut Chan-o-cha, Foreign Minister Don Pramudwinai and former justice minister Peerapan Saliratvipak are among those, who, to different degrees, have voiced concern about the activities of the foreigners showing up when Future Forward leader Thanathorn Juangroongruangkit turned himself in a few days ago to preliminarily answer national security charges. Prayut basically said he was waiting for more information on the matter whereas Don and Peerapan were a lot more critical, saying the westerners were way beyond the line and things like this could never have happened if the involved countries questioned their own national security suspects.

Don and Peerapan insisted what happened was tantamount to interfering with Thailand’s legal affairs.

“It is unprecedented that they (foreign diplomats) are present in the interrogation room,” said Don. “If they want to know about the atmosphere in the interrogation room, they should wait outside the police station.  No country will ever allow this.”

It is fast becoming a diplomatic row. The Thai Foreign Ministry has registered its concern. It charged in a statement that the diplomats’ action violate the Vienna Convention on diplomatic relations that states diplomats “have a duty not to interfere in the internal affairs” of the nation where they are posted.

The diplomats’ presence at the Thanathorn preliminary interrogation was fairly visible and the publicity it generated “were clearly and act of political significance, seen by the Thai public as a show of moral support to Mr. Thanathorn.”

The statement prompted quick responses. US Embassy spokesman Jillian Bonnardeaux was quoted by Khaosod as saying that the US involvement was normal. “The US Embassy regularly attends court proceedings in high-profile cases around the world in order to observe fair trial guarantees and respect for the rule of law,” she said, adding “This is a standard diplomatic practice.”

Khaosod said an EU delegation statement made a similar point. “Observation of hearings and trials is standard diplomatic practice worldwide,” the news outlet quoted the statement as saying. “The purpose is to enhance understanding of adherence to international standards such as human rights and due process.”

Thailand’s political conflict has led to major and minor diplomatic disturbances before, but the focus was mainly on the Shinawatras who have been living in exile. But Thanathorn’s party has won an unexpectedly large number of parliamentary seats in the March 24 general election, thus drawing massive local and international attention to his political ideology.

Signs are that the aftermath of the general election can increase the diplomatic tension, even in an unlikely event that the political alliance of which Thanathorn is a part manages to take political control. Thailand’s judiciary and legislature have proven to be independent of each other, as seen in the court verdict against Thaksin Shinawatra, which was delivered during a “democratic period” when political parties sympathetic with him were in power, and some party dissolution which took place without being preceded by a coup.

The names of Edward Snowden and Julian Assange, who was arrested by British police at Ecuador’s embassy in London on Thursday,  are being mentioned more and more by those scrutinizing the “fair treatment” argument now. Debate will continue and may last for a long time.