xecution in the State
in which it was rendered, as where the defendant left the State after
service upon him and took all his property with him. While the want of
power to enforce a judgment or decree may afford a reason against
entertaining jurisdiction, it has nothing to do with the validity of a
judgment or decree when made.[11] In the words of the Court in a recent
case: "A cause of action on a judgment is different from that upon which
the judgment was entered. In a suit upon a money judgment for a civil
cause of action, the validity of the claim upon which it was founded is
not open to inquiry, whatever its genesis. Regardless of the nature of
the right which gave rise to it, the judgment is an obligation to pay
money in the nature of a debt upon a specialty. Recovery upon it can be
resisted only on the grounds that the court which rendered it was
without jurisdiction, * * * or that it has ceased to be obligatory
because of payment or other discharge * * * or that it is a cause of
action for which the State of the forum has not provided a court
* * *"[12]

On the other hand, the clause is not violated when a judgment is
disregarded because it is not conclusive of the issues before a court of
the forum. Conversely, no greater effect can be given than is given in
the State where rendered. Thus an interlocutory judgment may not be
given the effect of a final judgment.[13] Likewise when a federal court
does not attempt to foreclose the State court from hearing all matters
of personal defense which landowners might plead, a State court may
refuse to accept the former's judgment as determinative of the
landowners' liabilities.[14] Similarly, though a confession of judgment
upon a note, with a warrant of attorney annexed, in favor of the holder,
is in conformity with a State law and usage as declared by the highest
court of the State in which the judgment is rendered, the judgment may
be collaterally impeached upon the ground that the party in whose behalf
it was rendered was not in fact the holder.[15] But a consent decree,
which under the law of the State has the same force and effect as a
decree _in invitum_, must be given the same effect in the courts of
another State.[16]

One result produced by not following Hampton _v._ McConnell is that even
nowadays the Court is sometimes confronted with the contention that a
State need not provide a forum for some particular type of judgment from
a sister State, a claim which