DONALD TRUMP marks his first 100 days back in power seemingly without the fix to the Ukrainian war he had once promised to secure on his first day. But the American diplomatic dial remains turned to max, with the secretary of state, Marco Rubio, describing the next seven days as “critical” and (again) threatening to walk away if there is no result. So far, talks have not squared the circle: reconciling Ukrainian insistence on security guarantees with a Russian desire for a public capitulation. But those close to the table speak of a new momentum. For the first time, Ukrainian negotiators are cautiously optimistic. “We are trying to improve our position,” says a senior Ukrainian official. “But there is bluffing on all sides. And the danger is someone overplays their hand.”