Today in History (1862) - The U.S. government forbids all Union army officers from returning fugitive slaves, thus effectively annulling the Fugitive Slave Law of 1850 and setting the stage for the Emancipation Proclamation. On the same day in 1865, the Confederate Congress voted to enlist 300,000 black troops, granting them freedom with the consent of their owners. Lee surrendered a few weeks later. |
I think this would be the equivalent of waving a red flag in front of Democratic Senators, as dispirited as they may be at the moment.
UPDATE: It doesn't actually have to be red to be a red flag.