An ethics scandal has cost one member of the New Hampshire Supreme Court his job and threatens three others — including the chief justice, who may soon face an impeachment inquiry by the state Legislature.

What began two months ago with a court clerk’s disclosure of unethical conduct has exploded into a constitutional crisis in the “Live Free or Die” state. It has also revealed a court practice that legislators say undermines the legality of past rulings and the credibility of present and former justices.