Barack Obama and Dick Cheney are squaring off in a grand debate about the character and the content of the American experiment.

Unfortunately, the U.S. news media, and much of the political class, is struggling to keep up. The same Washington elites that could not muster the energy for a serious discussion of holding the Bush-Cheney administration to account during a period of constitutional distress now dwells of personalities and strategems rather than the vital issue that is at hand.

We are told that the squabbling between the president and the former vice president has to do with enhanced interrogation and Guantanamo Bay. But those are footnotes to the real struggle.

This is a dispute about the extent to which a president is bound by his oath to uphold and defend the Constitution, and by the rules and regulations of a land where it has always been supposed that no man was above the law.

As such, it is the too-long delayed first gret constitutional debate of the 21st century.

The United States was founded as a constitutionally-defined republic.

Having broken the grip of a British monarch and his empire, the American revolutionaries set out to create a system of government that guarded against the imperial impulse.

They gave the first powers of government – those of lawmaking and the allocation of resources – to the legislative branch. The idea was that the many representatives of the people, pulling in directions dictated by personality, ideology and region, would reach a proper balance that could not be achieved by the executive branch.

Even this was considered insufficient protection, however. So the framers explicitly restricted the authority of the executive and afforded Congress the authority to impeach those any and all who exceeded that authority.

Neither the president nor the vice president was imagined at the founding of the republic as a policy maker. Both were expected to take their cues from Congress.

Well into the 20th century, the balance was maintained. But it began to be tipped as the executive, beginning with Harry Truman, assumed expansive warmaking powers. As the mid-20th century progressed, successive presidents expanded the reach and presumed authority of the executive branch; operating in secrecy, failing to consult Congress or to respect the rule of law. So evolved what historian Arthur Schlesinger Jr. characterized as “the imperial presidency.”

No American has been a more rabid exponent of the expansion of executive authority than Dick Cheney, who began imagining a more imperial presidency as an aide to Richard Nixon and has pressed the point ever since. Cheney, as his writings and speeches reveal, believes that in matters of national security – and to only a slightly lesser extent in more mundane matters of domestic policy – the administration that occupies the White House can essentially do as it chooses.

To Cheney’s view, the measure of a policy’s legitimacy is its presidential seal of approval. He dismisses the system of checks and balances, the separation of powers, the rule of law and the dictates of the Constitution as outdates and irrelevant impediments to the task of “getting the job done.”

Viewers of the television show “24,” with its stylized torture sequences, can imagine Cheney as an out-of-shape Jack Bauer. That’s certainly what he sounded like Thursday, when he dismissed concerns about following the law and adhering to basic principles as “recklessness cloaked in righteousness.”

Obama is something less than a righteous figure. Civil libertarians have found much to criticize in the compromises – on issues ranging from the release of photographs detailing past abuses to the retention of military commissions to a new and unsettling proposal for “prolonged detentions”– that the president portrays as “(updating) our institutions to deal with this threat” of terror. But Obama still regards those institutions as meaningful and necessary. Indeed, he suggests, that any war on terror can and must be waged “with an abiding confidence in the rule of law and due process; in checks and balances and accountability.” And he promises the consultations with Congress and the courts that the previous administration did everything in it could to avoid.

“[The] common thread that runs through all of my decisions is simple: we will safeguard what we must to protect the American people, but we will also ensure the accountability and oversight that is the hallmark of our constitutional system,” Obama declared on Thursdays. “I will never hide the truth because it is uncomfortable. I will deal with Congress and the courts as co-equal branches of government. I will tell the American people what I know and don’t know, and when I release something publicly or keep something secret, I will tell you why.”

That is the language of a republican in the founding tradition.

Obama is, to be sure, an imperfect republican, especially as he speaks of “prolonged detentions” and other rough stretches on the frame and fabric of the Constitution.

But the man who has assumed the presidency bows to the traditions with a language and regard that was missing from Cheney’s pronouncements.

For Obama, the Constitution “provides a compass that can help us find our way.”

For Cheney, the Constitution is no compass. It is a straight arrow pointing – through a narrow reading of his favored Article Two – toward an imperial presidency.

Cheney’s bold defenses of his own personal Constitution make the Republicans in Congress a sideshow. He is the prince regent of a reconstituted and profoundly radical Tory faith.

It is the former vice president, not the minority leader of whip, who defines the alternative to Obama’s presidency.

So we Americans find ourselves witness to a reprise of one the greatest debates – perhaps the greatest debate — not merely of this country’s journey but of all nations.

Will it be the rule of law, tempered by shared and balanced powers?

Or will it be one man, standing about constitutions and laws and dictating his own rules?

Make no mistake, this is a genuine debate between Cheney’s post-modern militancy and Obama’s old-school republicanism. Cheney is the radical here. Obama is the traditionalist. And, while it is certainly true that the current president would benefit from some pressure toward a stricter construction regarding the 8th amendment, the former vice president’s determination to sacrifice the Constitution on the altar of self-defined “pragmatism” has about it the stench of royalism.