The bottom line, according to Sawers, is that Russia wants eastern Ukraine more than the West wants to defend it. Moreover, he said, while Putin may not be the Russian leader Western governments had hoped to deal with, he's probably better than anybody waiting in the wings of the Kremlin.
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"As long as Mr. Putin sees the issue in terms of Russia's own security, he will be prepared to go further than us," Sawers said, discussing the possibility of further Western intervention in Ukraine and/or stronger economic sanctions. "So he would respond with further escalation on the ground – perhaps cyber attacks against us. We have thousands of deaths in Ukraine. We could start to get tens of thousands. Then what?"
The best possible result, said Sawers, might be locking the current state of play in the troubled region into a sort of stasis.
"Ukrainians look to us to help them have their chance to embrace the order and values we enjoy here in modern Europe," he said. "We and they may end up with a new debilitating frozen conflict in Ukraine, well into the future. That is a wretched outcome for Ukrainians. But it may be the least bad attainable outcome."
The hope in the West that a post-communist Russia might increasingly turn toward democracy has been dashed by Putin's return to aggressive nationalism. Worse still, he said, the alternatives to Putin might not be preferable.
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"The convergence between Russia and the West which we had hoped for after the Cold War won't happen while he is in charge. We now know that," Sawers said. "Any foreseeable change of power in Russia may well be for the worse. Managing relations with Russia will be the defining problem in European security for years to come."
Sawers, after leaving MI6, became a visiting professor at King's College, as well as chairman of Macro Advisory Partners, a London-based consulting firm.
Since his retirement, he has controversially argued that while terrorist attacks on cartoonists who mock Islam – specifically the Charlie Hebdo massacre in Paris – "cannot be justified on any basis whatsoever," westerners should recognize "a requirement for some restraint."
Sawers has also been a vocal defender of the controversial information gathering programs of western governments, particularly joint efforts between the U.S. and U.K.