He is one of the most outstanding American political scientists, Sovietologists, and specialists in Ukrainian studies. His work also focuses on nationalism, revolutions, and empires. He is one of the most well-known Americans of Ukrainian descent.

He was born in New York into a Ukrainian family from Lviv that managed to escape from the Soviet Union. He graduated from the prestigious Jesuit Regis High School in Manhattan and studied history at Columbia University (1975), where he later earned a Ph.D. in political science (1984).

He has taught at Columbia University, Lehigh University, and Harvard University and is currently a professor of political science at Rutgers University in Newark. He is the author of numerous books as well as a poet and painter.