Whenever anyone notices that the Bush administration is claiming powers of imprisonment, torture and surveillance that people once thought the Constitution was designed to prevent, White House spokesmen put on a solemn face and explain that it’s a different world since Sept. 11.

But from the ballyhooed prisoner “compromise” negotiated with a few rebel Republican senators, the change is actually bigger than that:

It’s a different world since 1215.

Not satisfied with cutting up the Constitution, the administration is now mangling the Magna Carta.

The compromise bill takes away from federal courts the right to hear habeas corpus suits from “unlawful enemy combatants” – such as the 400-plus now held at Guantanamo. In other words, although being held in U.S. custody on U.S. territory, prisoners would have no right to argue in court that there was no reason to hold them.

The idea that the government now doesn’t have to justify imprisoning people has been a hard swallow for a lot of people, including the usually accommodating Sen. Arlen Specter, R-Pa., chairman of the Judiciary Committee. Monday he held a committee hearing to express his opposition, and that afternoon complained to the National Press Club about the abandonment of habeas corpus.

“… (T)hat has been the way traditionally of determining whether the detention is lawful,” Specter said. “It’s been around for a long time, since the Great Writ (Magna Carta) in 1215.

“And it is emblazoned in the Constitution specifically that it can be suspended only in time of insurrection or invasion – rebellion or invasion. And we don’t have either of those present now.”

Of course, there’s still two years of the Bush administration to go.

The administration has a priority of limiting court oversight of its treatment of prisoners because it keeps embarrassingly losing cases. Most recently, the Hamdan case, filed by a Guantanamo prisoner, led to the Supreme Court striking down the proposed rules for military tribunals, on the grounds that the tribunals had no congressional authority and the administration was just making things up as it went along.

Lt. Cmdr. Charles D. Swift, the Navy lawyer who represented Hamdan, explained, “The legislation introduced by the president will see to it that no one else will be able to do what I did.”

There’s a 1297 edition of the Magna Carta in the National Archives. There’s even a replica, printed in gold, right in the middle of the Capitol.

Senators could send an intern down to read it.

“If you’re locked up in Guantanamo with access only to military tribunals,” said Douglass Cassel, director of the Notre Dame Center for Civil and Human Rights, “it’s a very poor substitute for what has been the bulwark of liberty for 800 years.”

And, as always, the details get worse.

The great triumph of the compromise is supposed to be a ban on the use of torture on prisoners – although the White House says that it, of course, will interpret just where the lines are. But without access to courts, it’s not going to be easy to enforce that.

And according to Tuesday’s Washington Post, the original compromise has now been further compromised, allowing for indefinite detention, without access to courts, of anyone who “has engaged in hostilities or has purposefully and materially supported hostilities against the United States. …”

Writes the Post’s R. Jeffrey Smith, “The definition applies to foreigners living inside or outside the United States and does not rule out the possibility of designating a U.S. citizen as an unlawful combatant.”

So the new compromise not only excludes unlawful combatants from habeas corpus but considerably expands the people who could qualify as unlawful combatants – and subject to imprisonment at the pleasure of the president.

In the Magna Carta, the barons of England forced the king to recognize the existence of rights he could not dismiss. They established a principle that has lasted across two continents and eight centuries.

Unfortunately, the people who signed off on this compromise weren’t barons.

They were just senators.