In contrast, a SCOTUS decision will be definitive. "If they agree with Judge Leon, this program will shut down—and they will be accountable," Wittes concludes. "Are there really five votes to do that? Leaving aside the doctrinal questions, I doubt it. When everything’s said and done, I can’t count five votes on the Supreme Court to bear that kind of responsibility for the next bad thing that might happen."

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The inner thoughts and feelings of federal judges are usually beyond our knowledge, but they're often more deferential to the executive branch when it invokes national security, so perhaps Supreme Court justices will let speculative fear of future terrorist attacks corrupt their jurisprudence, as Wittes predicts.

If so, they won't just undermine their own integrity. They won't just be derelict in carrying out their sworn duty. They'll also likely look back on their decision with regret as their countrymen conclude that they did the wrong thing at a crucial moment. U.S. history is full of officials who perpetrated or ratified excesses in the name of national security and were held in lower esteem as a result. Has anyone's legacy suffered for protecting wartime civil liberties too zealously?

Americans always look back in horror at excesses perpetrated at moments of perceived insecurity. The War on Terrorism is still going on, and already we're ashamed of the detainee abuse of the Bush years. Unless SCOTUS puts a stop to mass surveillance on tens of millions of innocent Americans, its members, including Chief Justice John Roberts—who bears special responsibility, having appointed every member to the FISA court—will go down in history as the shortsighted SCOTUS that stood by as an Orwellian surveillance state became reality, even as the government presented no compelling evidence it improved safety.

Justices Antonin Scalia and Clarence Thomas, who take pride in their originalist proclivities, will be remembered for betraying the Framers who tried damn hard to make general warrants illegitimate.

Future NSA abuses—and let's be candid, can any student of the recidivist agency's history doubt that they'll happen?—will be blamed partly on the justices who had an opportunity to restore sane, constitutional limits on government surveillance, but instead permitted a secretive, insecure, historically abuse-prone agency to keep building a database with sensitive details about the private communications of tens of millions of innocents over many years.

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No one thinks the Supreme Court's job is to prevent terrorist attacks, and it's highly unlikely that its members will ever be "held accountable" for one, whatever that means. But the Court is very likely to be considered partly responsible if the executive or legislative branch perpetrates unchecked constitutional abuses, because checking such abuses is core to the court's responsibilities. That's why being remembered for ratifying mass surveillance would be so shameful a legacy for members of the Supreme Court as they take their place in U.S. history.