President Donald Trump delivers remarks during a National Day of Prayer service in the Rose Garden at the White House May 02, 2019 in Washington, DC.

The U.S. could become one of the most protectionist countries in the world, if President Donald Trump's latest tariff threat materializes.

Trump tweeted Sunday that the current 10% tariffs on $200 billion worth of Chinese goods will rise to 25% on Friday. He also threatened to impose 25% levies on an additional $325 billion of Chinese goods "shortly." U.S. duties, already higher than those of most developed economies, would surge to levels above those of many emerging-market countries, where tariffs are more commonplace, CNBC's Steve Liesman pointed out.

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"If the U.S. follows through on the latest trade war threats it will raise the overall US tariff level to 7.5%, which is higher than in many emerging markets," Torsten Slok, Deutsche Bank's chief economist, said in an email on Monday.