Considering The Great Gatsby as social commentary, why do you think that Tom is an important character?

As social commentary, Fitzgerald draws a sharp distinction
between the East and the West. The East is associated with excess, irresponsibility,
immorality, and amorality. He develops an additional distinction among social classes in
the East. Tom Buchanan, as a member of the wealthy Eastern establishment, embodies the
characteristics of that most privileged social class, and in his scathing
characterization of Tom, Fitzgerald makes a strong critical statement about the social
class he represents.

Born to enormous wealth and a family
name, Tom Buchanan has attended the right schools, moved in the right circles, and
developed the arrogance and sense of entitlement that accounts for his moral bankruptcy.
Tom is an ignorant snob who bullies his way through life, secure in his superiority and
contemptuous of anyone who is not in his social class. Generations of family wealth have
corrupted his character and his soul. Fitzgerald's description of Tom and Daisy make his
condemnation of their privileged social class quite
clear:

They
were careless people, Tom and Daisy--they smashed up things and creatures and then
retreated back into their money or their vast carelessness or whatever it was that kept
them together, and let other people clean up the mess they had made . . .
.

Tom Buchanan is important
in the novel in developing Fitzgerald's social commentary because he represents an
essential element in the corruption of the once great American Dream. Generations of
inherited wealth have weakened the moral fabric of the country and undercut the
principles and values upon which it was founded.