“You don’t imprison your political opponents,” Durbin said on the Senate floor Tuesday. “You beat them in an election.”

In 2011, a Ukrainian court sentenced Tymoshenko to seven years in prison for financially benefiting from a gas deal her government struck with Russia.

Durbin said Ukraine is a “great nation” and has been helpful in international peacekeeping, but that imprisoning Tymoshenko would be something a more oppressive country would do.

The European Union has also suggested that he imprisonment is politically motivated.