What is his most likely reason for doing so?

From Richard Nixon’s “Checkers” Speech, September 23, 1952

paragraph 2 : “And so I felt that the best way to handle these necessary political expenses of getting my message to the American people and the speeches I made -- the speeches that I had printed for the most part concerned this one message of exposing this Administration, the Communism in it, the corruption in it -- the only way that I could do that was to accept the aid which people in my home State of California, who contributed to my campaign and who continued to make these contributions after I was elected, were glad to make…”

In paragraph 2 above, Nixon describes his political speeches as “the speeches that I had printed [that] for the most part concerned this one message of exposing this Administration, the Communism in it, the corruption in it.” What is his most likely reason for doing so?