They can't bluff him,
They can't bully or intimidate him, and
They can't bankrupt him.
Since the last military operation in Afghanistan, at the time of Soviet Union in 1980, Russia hasn't invaded any country, contrary to the allegations in the Western media. Russia didn't "invade" Chechenya, wich was included in the Imperial Russia in 1859.
Russia didn't "invade" South Ossetia, which was an automoumous provice and declared independence at the break of the Soviet Union in 1991, and it's still an independent Republic, not part of Russia.
Russia didn't "invade" Crimea, it already had there some 17,000 troops according to the treaty signed with Ukraine in 1994. Crimea has been part of Catherine the Great' Imperial Russia since 1774.
Contrary to the West allegations, that V.Putin wants to rebuild the Soviet Union, this is not his goal. What he wants is to regain the greatness of Russia as set up by the great precursors Peter and Cathrine II, at the end of 18th century, but a new, modern Russia. It is not a coincidence that the Russian Federation adopted the Imperial Russia's colors and coat of arms.
At that time the actual Eastern and South Ukraine, called "Malorussia" (Little Russia) was integral part of the Russian Empire since 1654, the natural border being on Dniepr river.
With this data in mind, one can understand Putin's foreign policy. He is not interested in Latvians , Poles or other Romanians, but only in rebuilding his country prosperity and greatness as he understands it.