The secretary of state’s trip comes amid an abrupt shift in relations between the United States and Europe after close cooperation during the Biden era.

Yet, in just under two months, NATO has been shaken to its core, challenged increasingly by Russia and the biggest land war in Europe since 1945 from the outside, and by the Trump administration from within, breaking with decades of relatively predictable U.S. leadership.

U.S. Secretary of State Marco Rubio will reportedly meet with Danish Foreign Minister Lars Løkke Rasmussen on the sidelines of a NATO gathering in Brussels, as U.S. President Donald Trump makes clear that he wants to take Greenland.

Matthew Whitaker was confirmed by the Senate to his role as U.S. ambassador to NATO. Whitaker, 55, who served briefly as acting U.S. attorney general during President Donald Trump's first term, was confirmed Tuesday night in a 52-45 vote to be America's representative to the 32-member state North Atlantic Treaty Organization,

The United States’ role in the NATO alliance has never been as precarious as it is now. In fact, it was earlier this month when Donald Trump declared that that the U.S. would not defend NATO member nations against an attack if those countries had not met defense spending benchmarks.

Whitaker, who previously served as interim U.S. attorney general in President Donald Trump's first term, was confirmed in a 52-45 vote Tuesday.