Questions Regarding Law: Exemptions Or Discretion As Applied to Laws

Questions Regarding Law: Exemptions Or Discretion As Applied to Laws

We all know that the law allows for exemptions/discretionary treatment. The most obvious example of course being self defense laws. Murder is illegal. Assault is illegal. Assault and/or murder enacted in an effort to defend oneself from an attack is allowed. However, my question here is should this discretion be extended to other laws?

Example 1

For example, stealing/theft. Let's say I'm a father of four and my children are starving. I steal $50 worth of food to feed the family for a week. Should I be charged with theft?

If you say yes, what if one of my children is literally starving to death? I'm stealing to literally save a life. Should I still be charged with theft?

Does it matter if I take from a fellow poor person or a billionaire?

Example 2

Let's say I am a police officer in court and I commit perjury to strengthen a weak case against someone I know for sure is guilty (not a feeling, I KNOW). Do I deserve to be punished for perjury? If so, do I receive any leniency at all? Let's say somehow that it truly and honestly came down to either me committing perjury or a guilty party walking free. I commit the perjury. What say you now?

What if it's the opposite? Perjury to aid an innocent person? Perhaps there is some information that may incriminate them, but is not directly related to the crime in question, and they are for sure innocent, but the information, if given, could be used by a crafty lawyer to smear the person and obfuscate the case against them? In the event that I lie to help the innocent person (and subvert the prosecutor's plans) should I/the person be charged then? If so, any leniency at all, or full extent of the perjury laws?

Example 3

In most places, purchasing/selling/growing and using/administering (to someone else) marijuana is illegal. In many of these places, this is a firm law. In some other places, exceptions are made for medicinal usage. Let's say I live in an area without these exceptions, and either myself or someone very close to me is in pain/discomfort/distress etc due to an illness, and marijuana provides relief faster/better/cheaper than anything else available. The marijuana is provided to the person/the person attains some/grows some. Should the person/provider face charges? If so, any leniency/discretionary treatment, or should they be punished to the full extent of the law?

Are there ANY crimes other than self defense for which you think you could make a case in favour of exemptions/discretion, and/or leniency?