Well, the Democrats are actually paying attention to the Constitution for once, trying to use it to argue that the entire notion of a debt ceiling is unconstitutional and that the government actually has unlimited borrowing power that cannot be checked. The argument has been put forward by Secretary of the Treasury Timothy Geithner, and taken up by others on the Left as Barack Obama continues to indicate his intransigent opposition to budget cuts and his hopeless infatuation with tax increases.

At a briefing with reporters on Wednesday, President Obama was asked whether he believed that the debt ceiling was constitutional or whether the 14th Amendment required the government to meet all of its obligations regardless of the debt-limit statute.

Obama dodged the question. "I'm not a Supreme Court Justice, so I'm not going to put my constitutional law professor hat on here," he said about the debt ceiling and a question on the war in Libya.

Treasury Secretary Tim Geithner, however, is less afraid of wearing that hat. At a Politico Playbook breakfast on May 25, Geithner was asked by host Mike Allen about the negotiations over default and the debt ceiling.

"I think there are some people who are pretending not to understand it, who think there's leverage for them in threatening a default," Geithner said. "I don't understand it as a negotiating position. I mean really think about it, you're going to say that-- can I read you the 14th amendment?"

Now let's look at the relevant portion of the Fourteenth Amendment.

Section 4. The validity of the public debt of the United States, authorized by law, including debts incurred for payment of pensions and bounties for services in suppressing insurrection or rebellion, shall not be questioned. But neither the United States nor any State shall assume or pay any debt or obligation incurred in aid of insurrection or rebellion against the United States, or any claim for the loss or emancipation of any slave; but all such debts, obligations and claims shall be held illegal and void.

Now the whole Fourteenth Amendment argument is an interesting one, but I don't think it works (Professor Balkin's view of the matter not withstanding). After all, nobody would be questioning the validity of the debt or the fact that it is owed. Indeed, the US government would continue to acknowledge the obligation to pay. What would be at issue would be the ability to pay as scheduled due to a crisis of liquidity.

Of course, as you point out, the ability to pay those debts ON TIME would still exist -- as you point out, that would simply require cutting from that portion of the government spending not dedicated to serving the debt.

Now there are two clearly constitutional options here:

• Congress and the President can agree to an increase in the debt ceiling -- which will require the President agreeing to cuts in spending for the GOP to support.
  
• The President directs the Treasury to withhold money from agencies and programs so as to keep the federal government from exceeding the debt ceiling.

There is, of course, a third option, one that is more contentious from a constitutional point of view -- Obama and Geithner keep borrowing in defiance of the debt ceiling. That will result in two things:

• Legal action questioning any debt contracted over and above the debt ceiling, on the theory that it is not authorized by law.
  
• The impeachment of Obama and Geithner for exceeding the Debt limit -- which is not to say that they will be removed (the Democrats control the Senate, after all, making removal unlikely). Depending upon the timing of the adoption of articles of impeachment, we may well be treated to the spectacle of a sitting president facing a trial before the Senate sitting as a court of impeachment while he is seeking reelection.

Ultimately, the ball is in the Democrats' court. They can act like responsible grown-ups and begin making the cuts that are necessary to preserve our nation's long-term financial solvency -- or they can argue that there is no limit to what the government can borrow and that the Executive Branch has the authority under the Constitution to take the United States deeper into debt than Congress has authorized. And that, my friends, undoes a key element of the separations of powers designed by those who wrote the Constitution in 1787.

UPDATE -- Here's a great article that explains this point clearly, concisely, and with reference to the entire Constitution.