The US held high tariff rates from 1816 until the middle of the 20th century. The US then cut tariffs more than most countries, often unilaterally, without also requiring tariff reductions by others. Today, the US has one of the lowest tariff rates among WTO members, and by far the lowest among large importing countries. Low tariff rates encourage import competition. The economic literature shows the large negative effect of import competition on manufacturing jobs, wages, and worker displacement.