A new distinction between two
kinds of state constraints is introduced and proved important for
solving the Ramification Problem in 
Reasoning about Actions. <em>Steady</em> constraints never, not even
for an instant, cease to being in force. As such they give rise to
truly instantaneous indirect effects of actions. <em>Stabilizing</em>
state constraints, on the other hand, may be suspended for a short
period of time after an action has occurred. Indirect effects deriving
from these constraints materialize with a short causal
lag. Carelessly mixing these two types of indirect effects is shown to
producing erroneous conclusions. On the basis of the existing theory of causal
relationships we illustrate how to deal with the distinction appropriately.