President Donald Trump's higher tariff rates of 10% to 50% on dozens of trading partners kicked in on Aug. 7, testing his strategy for shrinking U.S. trade deficits without massive disruptions to global supply chains, higher inflation, and stiff retaliation from trading partners.

U.S. Customs and Border Protection agency began collecting the higher tariffs at 12:01 a.m. ET after weeks of suspense over Trump's final tariff rates and frantic negotiations with major trading partners that sought to lower them.

Goods loaded onto U.S.-bound vessels and in transit before the midnight deadline can enter at lower prior tariff rates before Oct. 5, according to a CBP notice to shippers issued this week. Imports from many countries had previously been subject to a baseline 10% import duty after Trump paused higher rates announced in early April.

But since then, Trump has frequently modified his tariff plan, slapping some countries with much higher rates, including 50% for goods from Brazil, 39% from Switzerland, 35% from Canada and 25% from India. He announced on Aug. 6 a separate, 25% tariff on Indian goods to be imposed in 21 days over the South Asian country's purchases of Russian oil.

"RECIPROCAL TARIFFS TAKE EFFECT AT MIDNIGHT TONIGHT!," Trump said on Truth Social just ahead of the deadline. "BILLIONS OF DOLLARS, LARGELY FROM COUNTRIES THAT HAVE TAKEN ADVANTAGE OF THE UNITED STATES FOR MANY YEARS, LAUGHING ALL THE WAY, WILL START FLOWING INTO THE USA. THE ONLY THING THAT CAN STOP AMERICA'S GREATNESS WOULD BE A RADICAL LEFT COURT THAT WANTS TO SEE OUR COUNTRY FAIL!"