Marco Rubio's national campaign headquarters in Washington, D.C., has been evacuated Tuesdaya afternoon because of a suspicious white powder in a piece of mail. Emergency officials gave the all clear about an hour later, allowing Rubio's staff to return to work.

All clear after suspicious white powder sent to Rubio campaign HQ in DC. Workers who had been evacuated allowed back. Powder harmless

-- Steve Brusk (@stevebruskCNN) March 15, 2016