In the late 19th century, both American manufacturers and workers demanded high tariffs on goods imported into the United States. Why did they support this policy? They hoped to lower the price of imports because foreign goods were usually better quality
It would improve trade relations with foreign countries
They believed their jobs and goods would be protected from foreign competition
By making domestic goods more expensive, Americans would stand to make more money

They believed their jobs and goods would be protected from foreign competition.

Explanation:

During the late 19th century, America was in the process of industrialization, that is, the American economy was becoming one of the main manufacturing poles of the world.

In this context, American producers began to see how their products should compete with European products, which in some cases had more competitive prices, resulting in cheaper than products made in the domestic market. Therefore, many of these manufacturing entrepreneurs began to demand that the government impose tariffs on imports from abroad, with the aim of making foreign products more expensive in the domestic market, making American products cheaper and, therefore, more consumed, promoting national production and the economic development of American companies.