The “mystery of lawlessness” is “color of law” such as “mandates” made by tyrants without due process, and counterfeits true, God given natural law.
#Revival Bible note on 2 Thessalonians 2:1-12 CSB
[7] For the mystery of lawlessness is already at work… [10] and with every wicked deception among those who are perishing. They perish because they did not accept the love of the truth and so be saved. [11] For this reason God sends them a strong delusion so that they will believe the lie…