Russia has vetoed a resolution at the U.N. Security Council that would further investigate and determine responsibility for the chemical attack in Syria over the weekend. U.S. Ambassador to the U.N., Nikki Haley, told the Council that "Russia chose protecting a monster over the lives of the Syrian people."

The bottom line: This is not the first time Russia, which backs the Assad regime, has stood in the way of investigations into chemical attacks in Syria. But it comes as President Trump is considering strikes to retaliate over the attack, which would escalate tensions with Russia.