However, the relationship between Bozell and his brother-in-law had already begun to sour; in March 1966, when Buckley wrote a column warning that Catholics should not try to seek legislation that would impose on others their belief that abortion is murder, Bozell wrote a letter to the editors of "National Review" protesting that the column "reeks of relativism. ... Mr. Buckley writes in this instance as though he had never heard of the natural law." Buckley was stung by the letter and had composed a bitter reply, but decided against sending it. In 1966, Bozell published "The Warren Revolution", a scholarly critique of the Supreme Court of the United States under Chief Justice Earl Warren. Despite his relocation to Spain, Bozell remained conscious of US politics; he opposed the Richard Nixon administration, intoning in the pages of "Triumph" that by supporting Nixon's candidacy in 1968, the conservative movement had "ceased to be an important political force in America." (Buckley would later change his mind and would agree with Bozell on this subject.)