The whole point here is that the parties in question have been able to gain sufficient popularity that they do deserve the seats, but the government in question won't allow them to have them.
Use the Support Ruling Party spy mission, and ministers that do the same thing. If you aren't ruthless enough to suppress the dissidents then they are going to cause problems for you...just look at North Africa and the Middle East for what happens when a government doesn't suppress the opposition.
EDIT: In other words, the countries that don't have election can't get away with ignoring the fact that (because of "enemy" spy actions) the dominant party is no longer their own.
Oops: Meant to edit that post, not reply to it.