Across the vast geography and collection of peoples once known as the Soviet Union, deep links in everything from language to infrastructure, reinforced in the 20th century, remain key to pursuing -- or impeding -- agendas in the 21st.
And while the Soviet Union was dissolved in name with the stroke of a pen on December 8, 1991, its dissolution in deed, as vividly seen again in the current energy imbroglio, is still very much a work in progress.
"It's never easy to start anew with countries that used to be your provinces, or parts of your territory, as a lot of Russians still regard Ukraine," said Dmitry Trenin, head of the Carnegie Moscow Center think tank.
It is precisely this latent Russian tendency to regard the other 14 former Soviet republics as client states -- a tendency anchored in centuries of history -- that is at least part of the problem, experts say.
"It's really striking that... Russia has not developed a positive approach to what is arguably the most important country on its immediate periphery," Trenin said at a meeting of Russia experts last week in Washington.
Of Russia's former Soviet partners, three of them -- Latvia, Lithuania and Estonia -- are now part of the European Union while two others -- Ukraine and Georgia -- have, with Western encouragement, pressed drives to join the bloc.
Another five -- Kazakhstan, Uzbekistan, Turkmenistan, Kyrgyzstan and Tajikistan -- meanwhile are being courted by the world's other big powers, anxious to cement their own influence in strategic ex-Soviet Central Asia.
And in Europe, even Belarus, the country dubbed the continent's "last dictatorship" by the outgoing US administration, has shown signs of interest in better relations with the West.
The trend has left Moscow, long the center of power in Eurasia and the source of unity in the Soviet Union through most of the last century, nervous and unhappy.
Vladimir Putin once called the collapse of the Soviet Union the "greatest geopolitical catastrophe" of the 20th century. Though he said no one, including he, wanted it back, the remark has resonance in today's energy equation.
Putin, Russia's powerful president-turned-prime-minister, has also made no secret in recent years of his rising anger over US strategic inroads made into lands bordering, and until recently controlled by, Russia.
Nowhere have those inroads been more apparent than in Ukraine and Georgia, where popular uprisings applauded by the West in the past four years toppled Moscow-friendly regimes and replaced them with pro-US leaders.
In a New Year's Eve appearance with President Dmitry Medvedev, Putin warned that Ukraine should expect "severe consequences" if it interfered in any way with Russian gas exports to Europe passing through its territory.
Since then, some EU countries have reported shortfalls in their supply of gas from Russia. Moscow has accused Kiev of "stealing" while Kiev has countered that it was only trying to make up for willful Russian supply shortages.
It remains to be seen how Putin will respond to the apparent gas flow disruptions.
Though neither side has much to gain from a protracted standoff, experts say Russia, infuriated most recently by Ukraine's rush to help Georgia in last summer's war, is in no mood to give any quarter on the gas dispute.
The situation highlights a core reality about the pipeline network carrying Russian gas to Europe: It is a unified system built at a time when Russia and Ukraine were united in a single, gas-exporting state -- the Soviet Union.
Apart from mathematical formulas and human trust, there exists no structural way of separating Russia's gas exports to Ukraine and its gas exports to other countries further afield.