Every indication is that Trump will respond to an adverse Supreme Court ruling on any important issue with a full-throated assault on the court and on the very idea of judicial independence. That the court’s majority is conservative and Republican won’t matter. Sen. Mitch McConnell can testify to Trump’s lack of respect for his fellow Republicans; and for that matter so can Chief Justice John Roberts, whom Trump dismissed during the election campaign as “an absolute disaster” because of his vote upholding the “individual mandate” portion of the Affordable Care Act.

Supreme Court justices live in a different world than most of us. They are protected by life tenure, and swaddled in a day-to-day environment as obsequious as the biblical court of Nebuchadnezzar. They are rarely racially profiled at traffic stops, set upon by chanting thugs with tiki torches, or run over by cars at political protests. Ordinary citizens may feel the changing winds of politics more quickly and keenly than justices.

Yet politics, in somewhat distorted form, makes its way into their protective cocoon sooner or later. Is it possible that the Arpaio pardon will be the moment that the conservative justices, or some of them, realize that this is not an ordinary administration, and that the cases coming before them this fall have higher than ordinary stakes?

Judges are usually expected to put aside the present political meaning of legal issues—will this decision help my party or the other party?—and consider them under the gaze of eternity. Administrations come and go, the theory says; decisions about the meaning of statutes or the scope of presidential authority may persist long after this issue has been forgotten. The issue thus should ordinarily not be, “Will this help or hurt Trump?” but “In the long run, which conforms better to the wording of a statute or the structure of the Constitution?”

But what if the issue behind present cases is whether, four or ten years hence, we will have a Constitution or a self-governing republic at all? How clear would those stakes have to be before the justices will decide that they may be the only emergency brake cord in a government threatening to jump the tracks?

History isn’t encouraging. Judges frequently like to roar from the bench about their independence and high-mindedness; but when it comes to true independence, these lions of the law often turn cowardly. Times of war and emergency make them even more timorous. The court enthusiastically backed Woodrow Wilson’s World War I crackdown on civil liberties; it meekly surrendered to the Japanese Internment. In two Nixon-era cases, the court held that media outlets could publish the formerly secret Pentagon Papers, and that Nixon had to turn over the “smoking gun” tape to a federal court. But those decisions, historically, are anomalous.