Three months after protesters toppled Ukrainian President Viktor F. Yanukovych and his government, unleashing a wave of unrest and chaos, the country has elected a new president. But Russian President Vladimir Putin, who deployed troops to annex Crimea at his earliest opportunity, remains the key figure shaping Ukraine's future — and he is continuing to propel Ukraine toward something far more dangerous than a new Cold War.

By placing himself firmly in the driver's seat of Russia's future, Putin has simplified the task of those who seek to understand the country. In fact, his actions are guided by a single goal, and it is not the imperial ambition that is usually thought to determine Putin's actions. Instead, every policy is subordinate to Putin's goal of ruling Russia for as long as he lives.

Putin's ambition is not the result of a pathological lust for power. Instead, it is based on entirely realistic concerns for his personal safety.