In what sounded like a preview of what President Obama will tell the country Tuesday evening from the Oval Office, National Security Adviser Susan Rice laid out in the most unflinching terms the arguments, both substantive and emotional, for why the U.S. must act in Syria, her emphasis underscored in the written version of her speech distributed by the White House. Speaking at the New America Foundation on Monday, she used just about every card available to the administration; her own reaction as a parent to the suffering of the children gassed to death in Syria and the anguish of their parents; the specter of an emboldened Iran and North Korea if the U.S. fails to act; and finally, an appeal to our better angels, to an America that is, as Rice put it, “the one indispensable leader in the world.”