When Kissinger said that Nixon wanted to be accepted by the "Establishment," to whom did he refer?

Kissinger is suggesting that Nixon's perception of being
an "outsider" helped to drive he and his policies in order to find this appreciation. 
Nixon's background was outside of the establishment, being born a farmer's son in rural
California.  He was not born of wealth or privilege and went to local colleges in
California, as opposed to the "established" universities of the nation.  His "outsider"
status was most evident in his presidential election challenges with then- Senator Jack
Kennedy, born of wealthy background and a staple in the Harvard and East Coast
community.  Once Nixon ascended to political power, Kissinger's argument suggests that
Nixon never lost sight of his "outsider" status and sought to be "embraced" by this
established order of academics, wealthy, and those perceived to possess power.  It is a
critique that might make sense, but makes some assumptions.  The first would be that
Nixon's perception of "the establishment" never really changed, though so much of
America did change at the time.  During Nixon's ascendancy and reign of power, America
changed massively through social dissent and through political legislation and action. 
It seems odd that despite all of this change, Nixon's supposed desire to be accepted by
"the establishment" did not waver.  Additionally, Kissinger's direct association with
"the establishment" in his work at Harvard might also be a conflict of interest in
making the claim.  If Kissinger is suggesting that Nixon was victimized by his own
desire to be accepted by "the establishment," then his selection of Kissinger, a member
of the Harvard community, might be seen in a different light, in that Kissinger was not
selected on his merits but rather for his affiliation.  This is to say that while
Kissinger is not wrong in his assertion, it is important to keep in mind that the
complexity of the Nixon Presidency should not be reduced to solely base and conjecture-
driven psychological perceptions.