A mere 148 years after the end of the Civil War, Mississippi has become the last state to send in its paperwork on the 13th Amendment, which as you may recall was the one that abolished slavery.
Passed by Congress January 31, 1865. Ratified December 6, 1865.
Neither slavery nor involuntary servitude, except as a punishment for crime whereof the party shall have been duly convicted, shall exist within the United States, or any place subject to their jurisdiction.
That includes Mississippi.
Congress shall have power to enforce this article by appropriate legislation.
Most of the reports on this event so far have gone with headlines like ABC's "Mississippi Officially Abolishes Slavery, Ratifies 13th Amendment," and I suppose those are better headlines than the one above but they aren't exactly accurate. (I am not above tweaking a headline for humor value, of course, I'm just pointing out a fact.) What happened on February 7, 2013, was a technicality: the Mississippi Secretary of State officially informed the National Archives that his state had indeed ratified the 13th Amendment. For a reason that is still unclear, this notice wasn't given immediately after the state took that action, but everyone who is making fun of Mississippi for not "ratifying" the 13th Amendment until 2013 is being unfair.
It did that way back in 1995.
It may or may not be accurate to say that Mississippi has just "officially abolished slavery," depending on what is meant by that. Under Article V, amendments to the Constitution are "valid to all Intents and Purposes, as Part of this Constitution, when ratified by the Legislatures of three fourths of the several States" (or by state conventions but that's not how this was done). So slavery was actually abolished on December 6, 1865, when Georgia became the 27th of the (then) 36 states to ratify the 13th Amendment. And at that point the amendment was binding on the other 12, regardless of whether they ratified it or not. Still, it looks like most of the others went ahead and ratified it over the next few years. It probably seemed like the thing to do at the time.
Four states actually rejected the amendment outright; in addition to Mississippi, Delaware, Kentucky, and New Jersey also said no (symbolically). New Jersey changed its mind a year later, Delaware in 1901, Kentucky not until 1976, and Mississippi didn't get around to it until 1995. But again, slavery had been illegal in all the states (including later-joining ones) since 1865, so it doesn't seem accurate to say that these states were "abolishing slavery" when they did this. That had already happened whether they liked it or not.
As for the claim that ratification wasn't "official" until notice was given, that seems mostly wrong, because as Article V says ("valid … when ratified") and the Supreme Court has held, what matters is the date a state legislature votes to ratify, not the date it gives notice or the federal government "proclaims" ratification or anything like that. So it is more accurate to say Mississippi made its rejection of slavery "official" in 1995, although for strictly legal purposes, that didn't matter either.
The oversight regarding notice was cleared up this month after a professor at the University of Mississippi Medical Center took his family to see "Lincoln," which apparently ends by noting that there were a couple of loose ends still to be tied up on this whole slavery thing. He and a colleague then got a copy of the state bill and sent it to the state government, which promptly (this time) contacted the feds.