By Paul Reynolds
World affairs correspondent, BBC News website
The fall of Mikhail Gorbachev's USSR followed that of the Berlin Wall
Russia has been one of the great disappointments for the West following the fall of the Berlin Wall and the end of the Cold War.
But the Russians have their disappointments as well and I got a good insight into Russian thinking at a recent meeting in London addressed by Igor Yurgens, an adviser to President Dmitry Medvedev and the head of a Moscow think tank, the Institute for Contemporary Development.
He had, for me, some startlingly useful insights. Over Iran, for example. Whereas in Israel, the US and much of Europe, Iran is seen as a threat, the Russian attitude is more nuanced for a specific reason.
"We view the situation rather differently," remarked Dr Yurgens.
"Russia would like to play a positive role in the nuclear issue and President Medvedev told me that it was willing to go along with more sanctions.
"But for Russia, a key point is that Iran has not provoked trouble in the North Caucasus.
"Radical Islamists are very difficult but they [the Iranians] have behaved there with restraint and good manners."
The message here is that Russia will go so far, but not so far as to provoke Tehran, whose current behaviour along the sensitive southern Russian frontier has been positive for Russia. Russia's concern about Islamist influence was evident.
Such thinking illustrates the problems of getting a united diplomatic approach to Iran.
Afghanistan is another crisis in which Russian policy matters. Here again, the Russian fear of radical Islam can be detected.
It explains why Russia is basically quite sympathetic to the US-led Nato operation in Afghanistan.
"It would not be a birthday present for Russia if radical Islamists gained Afghanistan and Pakistan," Dr Yurgens said.
He pointed out that Russia allows Nato to resupply its forces through Russia and he suggested that this could be expanded.
He was critical of the way Nato expected quick results in Afghanistan. He was there himself during the Soviet era, during which time the Russians tried to build up the country's infrastructure and industry to provide jobs.
"That did not work," he said.
"Learn from our experience. The Taliban cannot be easily defeated. Even the Russians and British before them controlled only 40% of the country."
Igor Yurgens comes from the Medvedev camp, the more moderate half of the Russian government. He is on the advisory board of the London-based International Institute for Strategic Studies.
Debate still rages about what Moscow and Washington agreed over Nato
Yet, like most Russians these days, even he is full of suspicion about the US.
This suspicion, which is mutual, affects the whole relationship. It explains why there is such an ambiguity in Russian-US ties. On some issues, they co-operate well. But there is always a limit.
Some of the suspicion seems to be in the recent Russian psyche.
Dr Yurgens mentioned several times a promise given to former Soviet leader Mikhail Gorbachev by West German Chancellor Helmut Kohl "in the presence of President Bush senior" that Nato would not expand beyond its then limits if Soviet forces left East Germany.
One former Nato official in the audience challenged the value of this promise, saying that it was given in a very different time and place, when there was still a Soviet Union, but Dr Yurgens called this response "casuistic".
He also said that Mr Putin had been "bitterly disappointed by American friends and colleagues", culminating in the crisis over Georgia last year which was "one of the worst cases".
However, President Barack Obama had pressed the re-set button and there had been a surge of trust, he said.
Dr Yurgens was optimistic that the US and Russia would reach a strategic arms agreement as planned by next month and foresaw that they might eventually reduce their arsenals to 500 nuclear warheads on each side by 2018.
But, on the other side of the coin, he appeared reluctant to play up the significance of Mr Obama's decision to abandon the Bush administration's planned US missile defence system in Poland and the Czech Republic.
Instead, he mentioned Russian complaints that US Vice-President Joe Biden had spoken of giving Poland Patriot anti-missile missiles. He puzzled experts in the audience when he claimed that Patriots could carry nuclear warheads.
He warned that Russia might respond by sending Iran the S300 anti-missile system it wants.
This mixture of praise and blame, of hope and wariness, of friendliness and threat, was very much the theme of his address - as it is of current Russian foreign policy.