(Portland, OR)  --  Senator Jeff Merkley is calling for the resignation of Homeland Security Secretary Kirstjen Nielsen.  The call comes after Nielsen defended the Trump administration's policy of separating children from their immigrant and asylum-seeking parents at the Mexican border.  Merkley appeared on CNN's "Erin Burnett OutFront" yesterday and accused Nielsen of telling "a lot of whoppers" at a White House press briefing in which she defended the policy.  Merkley added that Nielsen should "absolutely, 100-percent" step down, adding, "We need somebody there with integrity."