WASHINGTON —President Donald Trump's trade agenda is about to enter a new phase, as the Republican moves forward − for now − with tariff hikes.

In the face of mockery for repeatedly backing down from previous big tariff announcements, Trump is increasing tariffs on aluminum and steel imports to 50%. And his administration told nations in a letter this week that they have until June 4 to provide an update on the status of individual negotiations.

The tariffs are expected to be a major topic of discussion during Trump's meeting on June 5 with Germany's new chancellor, Friedrich Merz, and in an as-of-yet unscheduled phone call that the White House says the United States president will be holding this week with his Chinese counterpart, Xi Jinping.

At the same time, court challenges threaten to keep his administration from enforcing county-specific tariffs.

The legal challenges to Trump's tariffs in court have only been a minor setback, Commerce Secretary Howard Lutnick said in a June 1 appearance on "Fox News Sunday."