The principle distinction between the terms 'lawful' and 'legal' is that the former contemplates the substance of law, the latter the form of law.

Explanation

(English-origin maxim.) "Lawful" refers to the substance of law (conformity with right and justice) while "legal" refers merely to the form of law (compliance with procedural requirements) — an act may be legal in form yet unlawful in substance.

Where this applies

• A defendant's arrest followed all procedural requirements — the officer had a warrant, read the Miranda warning, and booked the defendant by the book — making it 'legal' in form, but the underlying statute authorizing the arrest violated the First Amendment, making it 'unlawful' in substance.
• A city condemns a building following every required procedural step, making the condemnation 'legal,' but the purpose is to transfer the land to a private developer for private profit, making it 'unlawful' in substance.
• A tax is collected through all the proper administrative channels, making it 'legal' in procedure, but the tax was never authorized by the legislature, making it 'unlawful' in substance because it lacks the foundation of just law.