A lot happens every day. Alliances shift, leaders change, and conflicts erupt. With In Brief, we’ll help you make sense of it all. Each week, experts will dig deep on a single issue happening in the world to help you better understand it.***With Donald Trump now back in the White House, European leaders must determine how much support they will provide to Ukraine — and, more broadly, how to approach European security. Leaders in four key European states — the United Kingdom, France, Germany, and Poland — have to balance domestic political interests with changing regional and global factors. We asked