Samantha Power: Obama Believes Skipping Putin Meeting ‘Irresponsible’ Given Stakes

The US Ambassador to the UN appeared on "This Week."

She said the meeting between the two leaders scheduled for Monday is not an indication the U.S. strategy of isolating Putin has failed.

"A hallmark of President Obama's foreign policy from the beginning has been to test engagement," Power told ABC News' Martha Raddatz on "This Week."

Power accused Assad of targeting Syrian civilians and of being ineffective in the fight against ISIS. Her comments came days after the head of U.S. Central Command testified before Congress that only four or five Syrian fighters trained by American forces remain on the battlefield. Power conceded questions about the American strategy in the fight against ISIS are legitimate.

"This is a risk management exercise. We also have to grapple with the fact that if we weren't investing in Syrian-Arab forces and in moderate Syrian opposition forces, we'd be in a world where again, ISIL [ISIS] would be able to have a protracted presence without being displaced over time. So we need to invest in this, we need to get the vetting right, and I think DoD has in mind some improvements that will enhance our prospects," she said.