Chapter DIX: 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.