Washington (CNN)The serious escalation of fighting in Ukraine is pushing President Barack Obama closer to the proxy war with Russia that he has long sought to avoid. That prospect is increasing as the United States openly accuses its former Cold War foe of sending tanks and troops in unmarked uniforms across the border into eastern Ukraine, boosting separatists in their battle against Kiev's beleaguered forces. The revelations are sharpening Obama's dilemma as his White House considers whether to send "lethal" weapons, including anti-tank and anti-mortar systems to the outgunned Ukrainian armed forces. Obama's nominee to become the next Defense Secretary, Ashton Carter, bolstered that idea during his confirmation hearing on Wednesday.
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U.S. considering sending arms to Ukraine
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But critics fear move could escalate US-Russia showdown
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No one knows how Putin would respond
The push to arm @placeholder got another boost this week with a report by a group of eight influential foreign policy scholars -- including several former senior Obama appointees.