Diplomats, TSA, and the VCDR

From India's Economic Times, an incident highlighting the intersection between between current controversies and international law:

India Thursday termed as "unacceptable" the "pat down" search Indian ambassador Meera Shankar was subjected to in the US, the second time in three months, and said it will take up the issue. Washington however, asserted that diplomats were not exempt from the searches even as it expressed regret and agreed to look into the incident.

Looks like the Indian Government is a little LESS than pleased that Ambassador Shankar was given "a little something extra" on her way through Jackson-Evers International Airport. As Prof. Spiro notes over at Opinio Juris, the TSA's actions arguably violated the Vienna Convention on Diplomatic Relations (VCDR):

"The question for diplomatic immunity experts is whether TSA pat-downs are consistent with the Vienna Convention on Diplomatic Relations, article 29 of which provides:

The person of a diplomatic agent shall be inviolable. He shall not be liable to any form of arrest or detention. The receiving State shall treat him with due respect and shall take all appropriate steps to prevent any attack on person, freedom, or dignity.

Whether or not it constitutes a violation of the VCDR, TSA might as a policy matter send the word on down the line that diplomats should get kid- (not plastic-) glove treatment at airport checkpoints."

While Indian External Affairs Minister S.M. Krishna did not explicitly reference the VCDR in his statements to The Economic Times, he did reference "certain well-established conventions, well-established practices" in support of his nation's outrage over the incident. Does the VCDR explicitly address pat-downs? The closing phrase of Art. 29 - "prevent any attack on his person, freedom, or dignity" - is quite vague, so an argument could be made both ways.

Even if Art. 29 did not address pat-down like searches at the time it was drafted, India's outrage over the incident - and other nations' response to it - would be a sign of "subsequent state practice" that could help clarify the article's ambiguous meaning. Under the Vienna Convention on the Law of Treaties such incidents are some of the most authoritative sources in treaty interpretation, behind only terms' plain meaning and contemporaneous/subsequent agreements. Finally, there is always the possibility that the outrage over the incident will turn into a norm of customary international law - provided, of course, that the standard requirements of 1) general pattern or practice and 2) sense of legal obligation are also present.

In any event, I agree with Prof. Spiro's take on things. Even if it is technically TSA policy to subject diplomats to pat-downs, the better course of action would be to exempt such persons. Doing so would seem to comport with the spirit and purpose of the VCDR and help the United States maintain a positive relationship with India. Furthermore, the problem would appear to be one that could be solved simply by education - airport officials would be much less likely to cause international incidents.