Rule of law and equal application

The same law applies to everyone, including those who write it and those who wield it. The powerful are bound by the procedures they create — they cannot exempt themselves from prosecution, ignore court orders, or use the machinery of justice as a weapon against political opponents and a shield for political allies. Lawful processes, not personal will, determine outcomes; outcomes change through elections and through lawful amendment, not through selective enforcement or selective protection.

The rule of law is what makes a government rather than a regime. When it breaks down, what remains is the will of whoever happens to hold office: the law applies, or doesn't, depending on who you know and which side you're on. The abuses tracked here include defying court orders, pardons for allies or oneself, opening or steering politicized investigations, selectively declining to prosecute clear violations because of political alignment, refusing to enforce duly enacted statutes, and ignoring the procedural and reporting requirements the law imposes. The standard is symmetric: selective prosecution and selective non-enforcement are recorded whichever direction they cut.

Further reading: National Constitution Center Interactive Constitution — Article II (executive's duty to faithfully execute the laws). Library of Congress Constitution Annotated.