White House Press Secretary Jen Psaki justifies retaliatory airstrikes fired Sunday against "Iran-backed militias" on the Iraq-Syria border, citing President Joe Biden's authority under Article II of the US Constitution to use military force in defense of US personnel. The strikes come at a delicate moment as the United States blames Iran-linked Iraqi factions for recent attacks against Iraqi installations housing its personnel, while also hoping to work out a return to a nuclear deal with Tehran. SOUNDBITE