A glowing Raúl Castro, Cuban president, strolled arm in arm with Dmitry Medvedev, his Russian counterpart, through the restored colonial district of Havana late last week, topping off a remarkable diplomatic effort by Moscow to mend relations with its former cold war ally.

The visit was the last stop on the Russian president’s tour of Latin America that, according to experts, was designed to teach the US a lesson: Russia wants to show that it is prepared to meddle in Washington’s backyard, in response to US support for governments such as Ukraine and Georgia that Russia considers to be part of its sphere of influence.