There has been some talk that the President can act unilaterally to raise the nation debt limit based on Section 4 of the 14th Amendment to the Constitution, which provides in pertinent part that "The validity of the public debt of the United States, authorized by law . . . shall not be questioned". The argument has been made that since Congress has ALREADY authorized BY LAW each obligation represented in the national debt, by appropriating the funds for various expenditures, any overall "debt limit" is artificially redundant. It would be like writing a bunch of checks and then refusing to deposit the funds in your account to cover them. While a constitutional challenge of the debt limit law may be a defensible argument in the spirit of the 14th Amendment it is not unequivocally compelling, as the 14th Amendment does not expressly authorize what proponents are asking the President to do.
President Must Invoke 31 USC 3102 Action Page: http://www.peaceteam.net/action/pnum1082.php (Obama himself is a direct recipient of this action page)
With this context, it is astonishing that apparently nobody has bothered to read the text of Public Debt Law of 1941 itself, embodied in 31 USC 3101, which is what codifies a national debt limit. That law states that
"The face amount of obligations issued under this chapter and the face amount of obligations whose principal and interest are guaranteed by the United States Government (except guaranteed obligations held by the Secretary of the Treasury) may not be more than [some arbitrary huge number] . . . "
"With the approval of the President, the Secretary of the Treasury may borrow on the credit of the United States Government amounts necessary for expenditures authorized by law . . . "
By this section Congress gives the President the EXPRESS, inherent and unilateral authority to direct the Secretary of the Treasury to incur obligations to cover all expenditures authorized by law, which is to say the sum of the appropriations bills Congress has already passed. And as we have just so clearly demonstrated such obligations are immune from any so-called debt ceiling limitation. Surely there is some White House attorney smart enough to figure this all out as we have.