This is a centralized government that does not tolerate opposing political opinions.

The answer is: totalitarianism

Countries that adopted a totalitarianism system will view the government as a group of people that have complete authority toward the citizens. The citizens only exist in order to fulfill the will of the government.

Such countries would not tolerate any opposing view that discredit the government. Death executions toward those who discredit the government tend be very common in a totalitarian country.