That’s why Separation is needed. If Religion joined with government there would be a constant battle for overall control.
Most countries have an official religion meaning government pays for Religion. Religion is thereby under the control of Government but the official religion doesn’t have to raise money to exist. Religion is paid for by taxes.
American government is forbidden by law from having an official religion. That keeps the power of taxation away from religion. It keeps religion out of government thus providing more freedom for citizens than would be available if religion and government joined together. Government still has control of the people but it has less control than when religion and government join together to operate against the people. regardless of the good that emanates from Religion, it’s danger is the forced control is gains from being part of government. That’s never good because it’s anti-Liberty.
And the biggest competitor to Government is religion. When religion is separated from government, government is still in control. In America religion is under a soft control by government. Government must control religion indirectly and by subterfuge, stealth and deceit but it has control. Soft control is a simple as denying a permit. Soft control is requiring a study which then can be accepted or rejected thus denying approval until a study results in a plan government approves, which plan could take so long to complete and get approved that the project is shut down without appearing to be shut down.