Who is the historian to explain what's going on in Eastern Europe and global geopolitics right now? It's a hot market.
Maybe Anne Applebaum, who works as a journalist but has serious credentials and a substantial bibliography on eastern Europe and Russia. She writes mostly for The Atlantic (which is a pretty cheap online subscription, though I recently abandoned mine, getting tired of too much insular Americanism.)
Maybe Adam Tooze. Tooze is a British economic historian now teaching in the United States. He came to prominence with a big book called Crashed, which smart reviewers seemed to think was the best book on the 2008 global economic crash. These days his substack "Chartbook" (adamtooze.substack.com) is absolutely relentless in pouring out deeply researched opinions on just about everything going on. Free, mostly. (The image above is from his Chartbook #96, that takes the Ukraine crisis back to 1918.)
Maybe John Mearsheimer, if you lean to the idea that NATO forced Putin to invade Ukraine, because it's a law of politics that Great Powers must dominate smaller nations around them, and to hell with all that sovereignty and self-determination twaddle. In right-wing American publications, though he has an odd left-wing following too, for those who blame the American empire for everything. Did himself no favours in a New Yorker interview published March 1, which looked like Putin apologetics to a lot of readers.
Maybe Fiona Hill, British expat, biographer of Vladimir Putin, and eastern European policy expert at American universities, think tanks, and sometimes the White House. (She worked in the Trump White House, but Trump thought she was a secretary or the coffee girl, and she testified for his impeachment). Actually, if you want a break from Ukraine horrors, her book There is Nothing For You Here, particularly the memoir in its first half, is a terrific account, from her own lived experience in northern England, Moscow, and the United States, of how all three countries, from the 1980s to today, have created their own massive rustbelts, economic devastation of the working class, and much of the subsequent socio-political upheaval we live with today. Doing a lot of media, so she's all over YouTube right now (here on Colbert)
Who else? And whose twitter feeds to follow? Suggestions welcome.