President Obama's ambassador to the United Nations compared Syrian dictator Bashar Assad's atrocities in the ongoing civil war to the Rwandan genocide that took place during Bill Clinton's presidency 20 years ago.

"Twenty years from now, how will we reflect on this council's failure to help those people? How will we explain Council disunity on Syria 20 years after Rwanda?" Samantha Power said during a U.N. Security Council briefing on the prevention and fight against genocide. "Too often, we have done too little, waited too long, or been caught unprepared by events that should not have surprised us."

It's an uncomfortable comparison for a member of Obama's team to make, given his decision to negotiate for the destruction of Assad's chemical weapons -- a deal the dictator has failed to uphold -- rather than authorizing a military strike in response to Assad's use of the weapons against his own people, which Obama had previously declared a "red line" for him.

It's also uncomfortable for the president's national security adviser, Susan Rice, who, as a Clinton adviser, reportedly argued at the time against recognizing the genocide because of the political risks of inaction.

Power argued for a military strike against Assad in September. On Wednesday, she again argued for action: "Let them say in their time that we, in our time, moved beyond deadlock to unity, beyond remembrance to mobilization, and beyond mere promises to the kind of bold and concrete actions that end wars and stop genocide before the searing pain it causes can be heard in the cries of those left behind."