The Scott Act (1888) was a United States law that prohibited Chinese laborers abroad or who planned future travels from returning. Its main author was William Lawrence Scott of Pennsylvania, and it was signed into law by United States President Grover Cleveland on October 1, 1888. It was introduced to expand upon the Chinese Exclusion Act passed in 1882 and left an estimated 20,000-30,000 Chinese outside the United States at the time stranded.
Prior to the Scott Act, the governments of the United States and the Great Qing Empire of China had formed the Bayard-Zhang Treaty, whereby the Chinese government would restrict emigration to the United States, and in exchange, the United States government would crack down on discrimination and bad treatment of Chinese in the US.
However, the treaty met with considerable opposition, both in China (particularly Kwangtung province) and among the Chinese in the United States. Due to public pressure, the Chinese government chose not to ratify the treaty. The United States government responded by acting unilaterally to pass the Scott Act.
On October 8, 1888, Chae Chan Ping, a Chinese citizen and unskilled laborer working in San Francisco, returned to the US after a trip home to China. He was stopped at the port and denied entry. He challenged the denial and the case reached the Supreme Court. This case, Chae Chan Ping v. United States, was decided on May 13, 1889 in favor of the United States. The Supreme Court decision was an important precedent both for establishing the federal government's discretionary power over immigration and upholding the government's authority to pass and enforce legislation contradictory to the terms of past international treaties (the treaty in question being the Burlingame Treaty of 1868).