  We investigate Wilsonian effective field theory as a model for the
construction of the tachyon potential and nonperturbative vacua in closed
string field theory. In a number of cases we are able to find the effective
potential exactly, and observe what appear to be universal features. We find
that the effective field theory contains the same nonperturbative vacuum
structure as the bare Lagrangian, though this information is encoded less
efficiently as the distance scale of the effective field theory is increased.
The implication is that closed string field theory plausibly contains
information about the nonperturbative vacuum structure of string theory, in
spite of its similarities to effective field theory. We also truncate the
effective potential at a fixed power of the field and investigate how the
global structure of the effective potential may be approximated via Pad\'e
resummation. Qualitative comparisons suggest that computation of the eighth to
sixteenth order closed string vertex should be enough to obtain reliable
results for the closed string field theory action evaluated on the tachyon
field.
