Gunmen seize key cities of eastern Ukraine ; pro - Russian forces cause chaos . General Frum : Remark that military intervention ' n't work implies West will look away . Russia is using military force -- as opposed to its usual tool kit of corruption , intimidation , and no-return-address assassination -- to reclaim former Soviet-occupied territory . Frum : Ukraine threatens stability of Europe ; NATO observers need to monitor events . He says sanctions must hurt Russian investments ; Ukraine 's weak military cannot help .
Gunmen seize key cities of eastern Ukraine ; pro - Russian forces cause chaos . General Frum : Remark that military intervention ' n't work implies West will look away . Frum : Ukraine threatens stability of Europe ; NATO observers need to monitor events . He says sanctions must hurt Russian investments ; Ukraine 's weak military cannot help .