The de Gaulle family were very private. De Gaulle was deeply focused on his career at this time. There is no evidence that he was tempted by fascism, and there is little evidence of his views either on domestic upheavals in 1934 and 1936 or the many foreign policy crises of the decade. He approved of the rearmament drive which the Popular Front government began in 1936, although French military doctrine remained that tanks should be used in penny packets for infantry support (ironically, in 1940 it would be German panzer units that would be used in a manner similar to what de Gaulle had advocated). A rare insight into de Gaulle's political views is a letter to his mother warning her that war with Germany was sooner or later inevitable and reassuring her that Pierre Laval's pact with the USSR in 1935 was for the best, likening it to Francis I's alliance with the Turks against the Emperor Charles V.