Why did josiah strong write this . the perdominance of the anglo saxon race

Josiah Strong (1847 – 1916) was an American Protestant clergyman,  leader of the Social Gospel movement. In his book The predominance of the Anglo Saxon Race, he called for Anglo-Saxons to spread their superior establishments and values to what he described as inferior races. Civilizing savage societies was believed to be a call from God in preparation for a future when the world´s different races would compete for total domination.

the correct answer is:   the domino theory states that if one country in a region came under the influence of communism, then the surrounding countries would follow in a domino effect.