What does "Rechtsstaat" (a state under the rule of law) mean in Germany?

EDITORIAL LEARNING AID

Why is this answer correct?

For the “Leben in Deutschland” test, connect “The state must comply with the laws.” with the meaning of the question. This is the answer marked as correct in the official key. “The state is right.” is not part of the solution and points to a different issue. Learn the key term together with the complete correct answer instead of memorising only its letter.

This translation and explanation are editorial learning aids. The official German wording and answer key govern the examination.