It does not matter what argument Christians use to defend themselves - none of them work. Rationality is suspended, evidence deemed irrelevant, the outcome pre-determined.
The argument by which the Left win every battle is simple and single:
God is dead and everything is permitted.
This fact was first noted by Dostoevsky, a long time ago.
The assumption in all modern public discourse is that God is dead - God is not a reason for anything.
And the, correct, inference is that therefore - in an ultimate and bottom-line sense - everything is permitted.
Because God is dead in the West, and in particular in the public domain - the arena of general discourse; therefore everything is permitted, nothing is forbidden.
Because everything is permitted and nothing is forbidden, there is no reason to do or not do, allow or not allow, tolerate or coerce - and this is precisely the backdrop of assumptions which makes a trend to Leftism inevitable.
Even on the few and rare occasions when Christianity beats secular Leftism, it does so using secular Leftist arguments such as free speech, religious freedom, human rights, diminution of suffering, emotional manipulations, legalism and loopholes... and every such victory strengthens the principle that that is how public disputes ought to be settled. The exclusion of Christianity from the public arena is further solidified.
This brings clarity.
Tactics are doomed - so, focus on strategy.
Don't waste time finding the perfect argument - it doesn't matter, may do more harm than good.
Strength of personal faith and life, conversion of the nation - Christian priorities are the essentials, and they must also be the priority.