Chapter IV: 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.