It isn't.
The answer is Jesus Christ.
He is our only hope. We are where we are as a nation because we have thrown God out of our schools, institution, military, workplaces, homes, and our very hearts.
Our answer must come from God. Only He can heal our nation.
You are correct. The root of the problem is fundamentally spiritual, with disbelief and rebellion against God and His rule.
The solution is to go out and make disciples of the unbelievers, just as the Christians of the vicious and hedonistic Roman empire did.