Medvedev's message was unusual, and given that he posted it in English, it was clearly designed for an American audience. But for Russia-watchers, there was also an added irony to Medvedev's comments: The Russian prime minister sure knows a thing or two about weak presidents. He once was one.
Medvedev became president of Russia in 2008. He stepped into the role to replace Vladimir Putin, a friend of his from his days working for the city of St. Petersburg. Putin, who was limited to two consecutive terms as president by the Russian constitution, became prime minister. Medvedev only served one term as president before Putin returned to the Kremlin in 2008.
When Medvedev entered office, there was a lot of debate about what sort of president he would be. Many commentators suggested it was a "tandem" presidency, implying some sort of shared power between Medvedev and Putin. Others, however, suggested that it was far more likely that he would not hold the real power — as a U.S. Embassy cable (later leaked) put it at the time, in this situation he would play “Robin to Putin's Batman, surrounded by a team loyal to the Premier and checked by Putin's dominance over the legislature and regional elites.”
Briefly, there was a hope that Medvedev would pursue a less authoritarian and more liberal set of policies. In September 2009, Medvedev published an article that criticized the problems with Russian society and its economy. Notably, he called on Russia to end its “humiliating” dependence on exports of oil and other raw materials — a warning that later proved prescient. The next year he fired Moscow's powerful mayor, Yuri Luzhkov, an ally of Putin, further impressing critics.
Boris N. Nemtsov, a member of the opposition who was later murdered in Moscow, told The Washington Post that the firing meant “that Medvedev has a chance to be a real president.”
In hindsight, however, these were false starts. As the Der Spiegel's Christian Neef and Matthias Schepp later put it, Putin was able to “humiliate the president whenever he pleased” due to his dominant personal relationship with Medvedev. The prime minister was able to undermine many of Medvedev's initiatives, with dissidents arrested and legislation blocked. There's little legacy of the Medvedev era now: Putin even abolished the "daylight savings” time change implemented by Medvedev after he returned to the Kremlin.
When Putin announced in 2011 that he would run again for the presidency, few were surprised. The Washington Post wrote that Putin “has always been in charge” while the New York Times called Medvedev a “weak executive” whose initiatives were always subject to veto. Medvedev himself seemed resigned to it, too, telling Russian television before he left office that Putin was both more popular than him and more authoritarian.
Though some expected him to be pushed out of mainstream politics, Medvedev has stayed on as prime minister since 2012. Recently, he has become a somewhat controversial figure in Russian politics, in part due to his frequent gaffes (such as seemingly falling asleep at numerous events) and allegations against him in anti-corruption campaign led by opposition leader Alexei Navalny. Medvedev has been dubbed “the most hated man in Russia”; recent polls have given him an approval ratings in the 40s, half the level of approval for Putin.
The extent of Medvedev's current political influence remains a matter of debate. However, his tweets on Wednesday may have had some effect. The next morning, President Trump wrote with his own message criticizing Congress.