LONDON - President Vladimir Putin's declaration of the annexation of four regions in eastern and southern Ukraine signals the onset of a new and highly dangerous phase in the seven-month old war, one that Western officials and analysts fear could escalate to the use of nuclear weapons for the first time in 77 years.
Putin has previously threatened to resort to nuclear weapons if Russia's goals in Ukraine continue to be thwarted. The annexation brings the use of a nuclear weapon a step closer by giving Putin a potential justification on the grounds that "the territorial integrity of our country is threatened," as he put it in his speech last week.