Two years after the ratification of this treaty, a bill was introduced
to prohibit the immigration of Chinese labor for twenty years. Both
the great political parties had included the subject in their
platforms in 1880. The Democrats had espoused exclusion and were
committed to "No more Chinese immigration"; the Republicans had
preferred restriction by "just, humane, and reasonable laws." The bill
passed, but President Arthur vetoed it on the ground that prohibiting
immigration for so long a period transcended the provisions of the
treaty. A bill which was then passed shortening the period of the
restriction to ten years received the President's signature, and on
August 5, 1882, America shut the door in the face of Chinese labor.

The law, however, was very loosely drawn and administrative confusion
arose at once. Chinese laborers leaving the United States were
required to obtain a certificate from the collector of customs at the
port of departure entitling them to reëntry. Other Chinese--merchants,
travelers, or visitors--who desired to come to the United States were
required to have a certificate from their Government declaring that
they were entitled to enter under the provisions of the treaty. As
time went on, identification became a joke, trading in certificates a
regular pursuit, and smuggling Chinese across the Canadian border a
profitable business. Moreover, in the light of the law, who was a
"merchant" and who a "visitor"? In 1884 Congress attempted to remedy
these defects of phraseology and administration by carefully framed
definitions and stringent measures.[48] The Supreme Court upheld the
constitutionality of exclusion as incident to American sovereignty.

Meanwhile in the West the popular feeling against the Chinese refused
to subside. At Rock Springs, Wyoming, twenty-eight Chinese were killed