Former Russian president Dmitry Medvedev has become embroiled in a tense back-and-forth on social media that prompted U.S. President Donald Trump to announce he had ordered the re-positioning of two U.

Dmitry Medvedev has traveled a long way from his time as Russian president, when he once stood beside then-US President Barack Obama and declared that “the solution of many world problems depends on the joint will of the United States and Russia.

In the West, Dmitry Medvedev was once seen as a democrat who could liberalise Russia. In a stunning fall, he has been reduced to a rabid attack dog for Vladimir Putin who threatens Western capitals with nuclear weapons and launches into xenophobic rants on social media.