On February 13th, President Trump released a memorandum announcing that the White House will launch an official investigation into nations that have imposed tariffs on U.S. goods. This new policy is called the "Fair and Reciprocal Plan." Once existing tariffs are identified, he has ordered reciprocal tariffs be placed on those nations. It can be inferred that April 1st is the soonest any of these tariffs would be made effective. 

These tariffs will not be implemented immediately. After the warning, President Trump expects these nations to lower or eliminate their tariffs.

The investigation will examine factors President Trump believes are affecting the U.S. economy. As stated in his memorandum, these factors include:

(a) Tariffs imposed on United States products.

(b) Unfair, discriminatory, or extraterritorial taxes imposed by our trading partners on the United States businesses, workers, and consumers, including a value-added tax.

(c) Costs to United States businesses, workers, and consumers arising from nontariff barriers or measures and unfair or harmful acts, policies, or practices, including subsidies and burdensome regulatory requirements on United States businesses operating in other countries.

 (d) Policies and practices that cause exchange rates to deviate from their market value to the detriment of Americans; wage suppression; and other mercantilist policies that make United States businesses and workers less competitive.

(e) Any other practice that, in the judgment of the United States Trade Representative, in consultation with the Secretary of the Treasury, the Secretary of Commerce, and the Senior Counselor to the President for Trade and Manufacturing, imposes any unfair limitation on market access or any structural impediment to fair competition with the market economy of the United States.