It is a common mistake for political thrillers and sci-fi screenplays to dump too many characters in the openings. This gets very confusing quickly.
As a reader, I always feel the strongest choice is to introduce the protagonist alone, so that he/she stands out and is clearly identified in the mind of the reader.
Once the protagonist has been absolutely clearly painted, a page later, you can introduce them to a group of friends or colleagues, etc., and I’ll learn a lot more about that character by the reactions of the other characters.
Political thrillers and science fiction oftentimes involve A, B, C stories and a variety of characters from overlapping worlds. If you make the mistake of dumping all of those characters at the beginning of your script, the reader will immediately be confused, not know who the protagonist (or protagonists, protagonist/antagonist) is, and will get lost. It is too much information too soon.
The easiest and best way to negotiate a large cast of characters is for the reader to be firmly grounded with one character – or two – and then for me to get to know the other players through that individual and how he/she responds to them.
In addition, this is where it is very helpful to introduce non key characters simply by their role, POLITICAL ADVISOR, SENATOR, ASSASSIN, etc., and this way I will know as the reader not to get too emotionally invested in anyone who is not a named character.
Remember, clarity above all!