re: .

From Wiki:

The tariff history of the United States spans from colonial times to present. The first tariff law passed by the U.S. Congress, acting under the then recently ratified Constitution, was the Tariff of 1789. Its purpose was to generate revenue for the federal government (to run the government and to pay the interest on its debt), and also to act as a protective barrier around domestic industries.[1] An Import tax was collected by treasury agents before goods could be landed at U.S. ports.

Tariffs have historically served a key role in the nation’s foreign trade policy. They were the greatest (approaching 95% at times) source of federal revenue until the Federal income tax began after 1913. For well over a century the federal government was largely financed by tariffs averaging about 20% on foreign imports. There are no tariffs for imports or shipments from one state to another. Since the 1940s, foreign trade policies have focused more on reciprocal tariffs and low tariff rates rather than using tariffs as a significant source of Federal tax revenue.

Tariffs were the main source of revenue for the federal government from 1789 to 1914. During this period, there was vigorous debate between the various political parties over the setting of tariff rates. In general Democrats favored a tariff that would pay the cost of government, but no higher. Whigs and Republicans favored higher tariffs to protect and encourage American industry and industrial workers. Since the early 20th century, however, U.S. tariffs have been very low and have been much less a matter of partisan debate.

Prior to the American Civil War tariffs were generally low, but rose during its duration. At the end of the end of the war in 1865 about 63% of federal revenue was generated by excise taxes, which exceeded the 25.4% generated by tariffs. In 1915 during World War I tariffs generated 30.1% of revenues. Since 1935 tariff income has continued to be a declining percentage of Federal revenues.

Correct.

No American car company has designed a series of engines in order to cheat an emissions standard.