Without Ukraine, Russia cannot be an imperial power, according to the Polish-American geopolitical theorist and former national security adviser to President Jimmy Carter, Zbigniew Brzezinski. With it, Russia has the potential to become one again.
His remark comes to mind as President Putin began a three day visit to Ukraine ahead of Sunday's first round of the presidential elections there, to attend a military ceremony commemorating the 60th anniversary of the Red Army's relief of the country from Nazi occupation.
The election, to replace the ten year rule of Mr Leonid Kuchma, pits the equally Russophile prime minister, Mr Viktor Yanukovych, against a liberal and pro-Western candidate, Mr Viktor Yushchenko.
Mr Putin openly favours Mr Yanukovych, who has campaigned on a programme of building closer relations with Russia, including dual citizenship and more integrated energy supplies. Under Mr Putin, Russia has cancelled Ukraine's energy debts and reached agreements on long term supply of oil and gas.
In the Polish parliament a former head of the country's intelligence said on Wednesday that "we are facing a restoration of the Russian empire through economic means and with the principle: yesterday tanks, today oil". This reflects a widespread concern in central and eastern Europe about the direction of Mr Putin's policies.
It is shared in Washington, which is worried by Mr Kuchma's decision last summer to abandon the objective of joining NATO. Mr Yushchenko, who campaigns in favour of eventual Ukrainian membership of the European Union, has widespread support in the western part of Ukraine, whereas his rival's main base is in the eastern part of the vast country with its 50 million population, where there is a large Russian-speaking minority.
By all accounts this election is running close. Opinion polls show a 50-50 division of opinion. There have been many reports of dirty tricks, irregularly subsidised campaigning and media manipulation, as well as strong involvement of well-known Russian, European and US figures.
Ominously, Mr Kuchma has been warning of possible violence if the result is disputed by the opposition and hinting that action would be taken against them. Assuming the election goes to a second round on November 22nd, a lot more international attention will be directed at Ukraine.
While opinion there is sharply polarised, many Ukrainians also resist either/or choices between eastern or western identities and alignments. But like Poland before it, Ukraine seems destined to be a cockpit of such geopolitical conflict in coming years.