If you still believe there is some overarching goal—new trade deals, negotiating for lower trade barriers, or whatever—to the Trump administration's trade policy agenda, Monday's announcement of new tariffs targeting imports from South Korea ought to put an end to all that.
South Korea was not the only country whose goods were hit with higher tariffs on Monday, nor does it seem likely to be the last. President Donald Trump also announced higher tariffs targeting imports from Japan, Myanmar, Laos, South Africa, Kazakhstan, and Malaysia. The White House indicated that Trump will be sending letters to other countries in the coming days announcing various tariff rates. This is, in effect, a slow-motion repeat of the "Liberation Day" tariff announcements that were put on hold for 90 days in early April after the markets reacted negatively to those announcements.
Still, tariffing imports from South Korea, America's sixth-largest trading partner, is particularly galling. If Trump's goal here is to strike deals that will lower foreign barriers to American exports and deliver better trading conditions for American manufacturers (who rely on imports), then hiking tariffs on South Korea makes startlingly little sense.