Law of Liberty is the rational solution to the idea of Evil. In Western religion, Evil is usually perceived as one of two opposing principles or forces. Evil being any any action, thought or attitude that is contrary to the nature or will of God.

There are those who actually believe that evil is a force or a substance. Many even believe it has a physical quality and can be transferred from one person to another.

Those who accept that there is such a thing as evil are bound by laws created by men.

The Law of Liberty 
Paul, in his epistles, tries to explain this law.  In his letter to Titus he says:
Unto the pure all things are pure: but unto them that are defiled and unbelieving is nothing pure; but even their mind and conscience is defiled.
Don't give heed to Jewish fables, and the commandments of men.

And again in his letter to the Romans, he repeats;

There is therefore now no condemnation to them who walk not after the flesh, but after the spirit Romans 6:1

I know, and am persuaded by the Lord Jesus, that nothing unclean of itself: but to him that esteemeth any thing to be unclean, to him it is unclean.   Romans 14:14.

And in his letter to the Galatians:

For you, brethren, have been called to liberty; only do not use liberty as an opportunity for the flesh, but through love serve one another. Galations 5:13


James speaks about it also.

But whoso looketh into the perfect law of liberty, and continueth therein, he being not a forgetful hearer, but a doer of the work, this man shall be blessed in his deed.  James 1:25

What does all this mean?

The basic original Christian doctrine was that we should no longer abide by the law of Moses, a law of carnal commandments, but that we should abide by the Spirit, which whispers in our soul and guides us along the right path.  It is explained that the law is only a temporary guide that cannot cover every possibility. It is necessary only until we have attained the spirit. When we attend to the voice of the spirit we make correct judgements in accordance with the situation in which we find ourselves.


Situation ethics

Situation ethics is the philosophical equal to the spiritual Law of Liberty. It takes into account the particular context of an act when evaluating it ethically, rather than judging it according to some set of absolute standards.

In other words, all laws and rules and principles and ideals and norms, are only valid if they happen to serve agape (total harmony), and thus may be broken or ignored if another course of action would achieve a more harmonious outcome.

Situation ethics began with an American thinker, Joseph Fletcher. If something is contrary to the Law or the Bible, it cannot be allowed whatever the situation. So, if you find out that a madman has bought nuclear weapons, you could not steal them from him to save the world, because stealing is wrong.  Similarly, if a 12 year old girl was raped and became pregnant, she could not he allowed an abortion because abortion is a sin.  Fletcher felt that this was wrong and said that Christians should only follow the Bible and/or the Church if it was the most loving thing to do. Therefore, a Christian would work out that the most loving thing to do in the situation of the nuclear weapons would be to steal them..

Situation Ethics or the Law of Liberty, it's all the same.