Complex sentence: To do the reverse and attack the Filipinos first the Filipinos would turn to the Japanese to arrange resistance to the campaign, even if the Filipinos were broken then the Republicans would have to challenge the Japanese who had organized the Filipinos.
Split into simpler sentences: To do the reverse and attack the Filipinos first, the Filipinos would turn to the Japanese to arrange resistance to the campaign. Even if the Filipinos were broken then the Republicans would have to challenge the Japanese who had organized the Filipinos.