If these people are basing their arguments on morality, then it is not possible to have a resolution. this is because morality is subjective, and always changing. Accoding to dictionary.com there are these deffinitions

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mor·al /ˈmɔrəl, ˈmɒr-/ Pronunciation Key - Show Spelled Pronunciation[mawr-uhl, mor-] Pronunciation Key - Show IPA Pronunciation
â??adjective
1. of, pertaining to, or concerned with the principles or rules of right conduct or the distinction between right and wrong; ethical: moral attitudes.
2. expressing or conveying truths or counsel as to right conduct, as a speaker or a literary work; moralizing: a moral novel.
3. founded on the fundamental principles of right conduct rather than on legalities, enactment, or custom: moral obligations.
4. capable of conforming to the rules of right conduct: a moral being.
5. conforming to the rules of right conduct (opposed to immoral): a moral man.
6. virtuous in sexual matters; chaste.
7. of, pertaining to, or acting on the mind, feelings, will, or character: moral support.
8. resting upon convincing grounds of probability; virtual: a moral certainty.
â??noun
9. the moral teaching or practical lesson contained in a fable, tale, experience, etc.
10. the embodiment or type of something.
11. morals, principles or habits with respect to right or wrong conduct.

number 3 seems to be the most pertinant to this discussion. the fact that morality is something outside of legalities. the legal system deals with 'right and wrong' whereas a moral system is concerned with 'good and bad' the two do not always intermix.

furthermore the fact that morality is subjective and changes throughout time is ALL the more reason why it SHOULD NOT be included in the legal system. A commonly used example is the civil rights movements. Segregation was the law, and therefore it was right. however it was not good.
Marijuana prohibition is the law (federally) so it is 'right' to follow it, you cannot say it is morally 'good'