The Chinese Exclusion Act was the first measure to specifically exclude an ethnic group from immigrating to the United States. It formed the basis of American anti-Asian immigration policy and was not repealed until 1943, when the United States and China became allies during World War II (see World War II and immigration). When the Chinese first came to California in large numbers, in the 1850s in the wake of the gold rush, they were generally well received as among “the most worthy of our newly adopted citizens.” By the 1870s, they constituted almost 10 percent of the population of California, but with the economic hard times of the 1870s, many westerners blamed the 100,000 Chinese immigrants for taking jobs and depressing wages. Increasing agitation from the early 1870s was for a time deflected by merchants, industrialists, steamship companies, missionaries, and East Coast intellectuals who argued in favor of the Chinese presence in America. By the late 1870s, politicians in the Midwest and East took an interest in placating an increasingly violent white labor force and thus were inclined to agree to limitations on Chinese immigration. In addition to organized opposition from labor groups such as the Workingmen’s Party, RACISM played a large role in anti-Chinese attitudes. Growing anti- Chinese opposition led to passage of the Page Act (1875) and appointment of a Senate committee to investigate the question of Chinese immigration (January 1876). In 1879, Henry George published Progress and Poverty, one of the most influential economic tracts of the 19th century, in which he concluded that the Chinese were economically backward and “unassimilable.” In the same year, President Rutherford B. Hayes encouraged Congress to examine ways of limiting Chinese immigration. After much debate and many abortive bills, the United States and China signed the Angell Treaty (1881), which modified the Burlingame Treaty (1868) and gave the United States authority to regulate the immigration of Chinese laborers. A bill was quickly brought forward to exclude Chinese laborers for 20 years, but it was vetoed by President Chester A. Arthur, who argued that such a long period of exclusion would contravene the articles of the Angell Treaty. Arthur reluctantly signed a revised measure on May 6, 1882. Its major provisions included 1. exclusion of all Chinese laborers for 10 years, starting 90 days from enactment of the new law 2. denial of naturalization to Chinese aliens already in the United States 3. registration of all Chinese laborers already in the United States, who were still allowed to travel freely to and from the United States Chinese officials and their domestic servants were exempted from the prohibition. In 1888, the Scott Act imposed new restrictions on Chinese immigration. The exclusions were extended in 1892 and again, for an indefinite period of time, in 1902. As a result of the 90-day deferral period, almost 40,000 additional Chinese laborers entered the United States, raising the Chinese population to about 150,000.