Just suppose that Christianity is outlawed in the United States. That is not as far-fetched as you might think.
Christians are already being banned on social media sites because the message of the gospel is considered hateful and divisive. Christians all over the world are losing government protections. As the movement toward globalism increases, constitutional protections are systematically being done away with. These protections presently act as a check against persecutions of various groups that do not behave in accordance with the politically correct edicts of the globalist elites.
There are a few scenarios that I can envision:
The globalists that have already attempted several assassination attempts against President Trump will be successful in removing him from power by any means necessary. Then will follow a backlash against evangelical Christianity that supported him in the last election.
The Lord returns to catch the church away and leaves behind those whose faith was in their church system rather than in the Lord Himself. This will result in a rapid movement toward global governance.
There will be time of great awakening and Spiritual revival before the Lord returns as a result of the success of President Trump and the patriots that believe in preserving sovereign nation states. Their success will expose the satanically inspired criminality of the global elites with their policies of fomenting wars and instability through international politics, human trafficking, drug trafficking and currency manipulations.
Some combination of these three scenarios.