Hearing this upsets most people, but St. Paul had a habit of inserting his own ideas into his letters rather than sticking to what the Holy Spirit said.
1 Tim. 2:1 - "... I ask..."
1 Tim. 2:8 - "... It is my wish..."
Contrasted with this is direct revelation from God given to St. Paul;
1 Tim. 4:1 - "The Spirit clearly says..."
... And so on throughout his letters.
Good points...
Other than The decree of King Darius in Ezra, I havent found an actual order from God to pray for those in authority..
But, meanwhile, Jesus said..
But I say unto you, Love your enemies, bless them that curse you, do good to them that hate you, and pray for them which despitefully use you, and persecute you; Matthew 5:44