Section 4 of the Fourteenth Amendment to the U.S. Constitution reads:
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.
While the Fourteenth Amendment, which was in part adopted to allay fears about the good faith of the US government post Civil War, says nothing explicitly about raising the debt ceiling or paying federal employees, it certainly does say that debts incurred legitimately by the United States government are to be paid and that failure to pay those debts is prohibited by the Constitution itself. A later section of the same Amendment gives Congress the authority to implement this amendment.
On the surface, it would appear that the House Republicans and Speaker Boehner are in the process of acting, or at least threatening to act, unconstitutionally! It would further seem that if the Speaker declines to do his constitutional duty and allows the country to default thereby throwing the domestic and international economies into chaos that it would well be in the emergency powers of the President to act unilaterally to restore the good credit of the nation. If President Obama were to exercise his emergency powers, while the far right would no doubt begin a movement for his impeachment, he would be acting in the courageous company of both Lincoln and Roosevelt.
If the House and its Speaker refuse to do their duty and follow the Fourteenth Amendment, the President should call them out on this matter and if that fails muster the courage to assume his emergency powers for the good of the nation and the world economy.
Just finished reading the NY Times and Princeton History Professor Sean Wilentz apparently agrees with me. http://www.nytimes.com/2013/10/08/opinion/obamas-options.html?ref=opinion