First of all SPECAT isn't a level above Top Secret, any more than NOFORN, NATO, etc.. In fact there is no level that's above Top Secret, just
compartmentalized info that happens to be Top Secret, based on need to know. Secondly, folks from the units above would be the last people that their
fellow countrymen would have to worry about being oppressed by(De Oppresso Liber isn't just a catchy slogan).
Lastly, in the event of a nuclear strike, or threat of one, martial law might come into play, whereby Posse Commitatus wouldn't be an issue. If
there are terrorist groups in the country, SOF forces would be far more capable against them than police forces. This OPLAN if it exists as portrayed
wouldn't be Top Secret anyhow.
Here's the criteria for classification-
Although the classification systems vary from country to country most have levels corresponding to the following United States definitions (from the
highest level to lowest):
Top Secret (TS)
The highest level of classification of material. Such material would cause "exceptionally grave damage" to national security if publicly available.
Such material would cause "serious damage" to national security if publicly available.
Such material would cause "damage" or be "prejudicial" to national security if publicly available.
Such material would cause "undesirable" effects if publicly available. Some countries do not have such a classification.
Technically not a classification level, but is used for government documents that do not have a classification listed above. Such documents can be
viewed by those without security clearance.
Classified information at the Confidential, Secret or Top Secret level can be further restricted by being additionally categorized as Sensitive
Compartmented Information (SCI) or Special Access Program (SAP) information. This applies to certain intelligence sources, methods, or analytical
processes that require additional access control measures. SCI or SAP information is labeled by letter codes that indicate which program the
information is a part of.