Emancipation Day should be January 1 to my way of thinking, since the Emancipation Proclamation was issued Jan 1, 1863. But there a couple of problems with that -- Jan 1 is already overloaded as a holiday, and the EP didn't apply to all slaves, just those in areas of the Confederacy not already under Union control (as is most remarkably demonstrated by the fact that it only applied to some parts of Louisiana). Juneteenth has an emotional appeal because it commemorates the first enforcement of EP in Texas, although it is not clear to me (I am sure there are sources I have not found) how long it took for the EP to be acknowledged Texas-wide. Strictly speaking, a better date to hook a holiday onto would be the date the 13th Amendment was passed by Congress, or the date it was ratified by enough states to be effective (3/4 of the states, but of which states?, since some states took a few years to reconstitute viable legislatures). Those dates are January 31 and December 6, 1865.
A meaningless appendix -- the passage of an Amendment to the US Constitution by Congress does not require the signature of the President to become effective.
