I wrote a diary before on how the debt ceiling is an anachronism (Sorry I didn't join n after the sudden influx of comments). I think there is an avenue for citizen action on this. If you own any type of federal bonds, either in a mutual fund or directly, you will not receive the interest due to you.
Also important, if interest due is not paid, then suddenly a risk premium will be added on, and increase in bond yields decreases the value of current bonds you hold. If that risk premium exists for the life of the bond (say if you own a 6 month T-bill), you have suffered irreparable harm. This would give bondholders legal standing to ask a court to issue at least a temporary injunction allowing the Treasury to issue debt as needed to allow the government to run until September 30th at the very least with no problems.
In Perry v United States (1935), the Supreme Court said:
Congress cannot use its power to regulate the value of money so as to invalidate the obligations which the Government has theretofore issued in the exercise of the power to borrow money on the credit of the United States.
The law currently funding government operations is not a suggestion - it is a requirement that the executive spends monies in accordance with those rules. As it stands now, the debt ceiling is preventing the executive branch from following the law. Congress' inaction on the debt ceiling would seem to violate Perry, and Section 4 of the 14th 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.
An alternative to a bondholder lawsuit would be for Obama to simply order the Treasury Department to resume new bond sales, with the OLC basically using this same argument I used here to justify it. This is not unitary executive mumbo jumbo, there are many laws which contradict each other it is well within the power of the President to implement the one that he thinks is legal.
The conservatives would call him a socialist power grabber (what else is new) but would they have a case? What standing do they have to sue? Taxpayers have limited standing most of the time. The Republican House voted to created this debt already, so what would they be arguing?
I could be wrong in all of this - I am not a lawyer, I just play one online - but maybe someone in this large community of activists can get something done.