The vote was a cliffhanger, and in the end, 375 absentee ballots cast by soldiers made the difference. Thus did the voters of Maryland narrowly adopt a new Constitution in 1864 that uniquely among border states still in the Union freed tens of thousands of enslaved men, women and children.

Gov. Augustus W. Bradford certified the vote Oct. 29, and the new Constitution went into effect Nov. 1, which makes this Maryland Emancipation Day and the 156th anniversary of a seminal event little remembered or celebrated throughout the state and nation.

Small local events in Montgomery and Anne Arundel counties have long been overshadowed by Juneteenth, marking June 19, 1865, when enslaved Texans learned that they’d been free since President Abraham Lincoln issued his Emancipation Proclamation on Jan. 1, 1863. The proclamation applied only to states in rebellion and left intact slavery in Maryland, Kentucky, Missouri and Delaware, which had not seceded.

Last July, the city of Rockville voted to make Juneteenth an official municipal holiday. In June, Maryland Gov. Larry Hogan (R) proclaimed June 19 Juneteenth Day. New York Gov. Andrew M. Cuomo (D) recently signed legislation making Juneteenth an official state holiday starting next year, with state employees off on “a day which commemorates the end to slavery in the United States.” Except it didn’t.

“One of things we don’t understand is that emancipation and freedom comes at different times for different people,” said Cheryl LaRoche, a University of Maryland professor of African American history. “Freedom is a place. I’m free across the street but not over here.”

The 13th Amendment to the U.S. Constitution abolishing slavery in all states didn’t take effect until Dec. 18, 1865, allowing slavery to continue in the border states. Maryland was the exception.

To give Maryland its due, state Sen. Arthur Ellis (D-Charles County) introduced a bill last year to make Maryland Emancipation Day an official paid holiday, with state offices closed and employees off. A fiscal analysis said it would cost the state millions of dollars, and the bill died in committee. Ellis said he intends to reintroduce the bill in the next General Assembly.

“I’m hoping as we go forward, more and more people will know about it,” he said. “This is unique history.” It is also complicated history.

Maryland’s population in 1860 contained an almost equal number of free and enslaved African Americans — 83,942 free Blacks and 87,189 enslaved — with slavery deeply embedded in Southern Maryland and the Eastern Shore. But abolitionists controlled the constitutional convention that convened in Annapolis from April to July. Pro-slavers failed to block provisions requiring voters to take a loyalty oath to the Union and allowing soldiers to vote absentee from the field.

Although not in the draft Constitution, there remained a presumption of compensation for loss of enslavers’ human “property,” valued at $14 million to $30 million. Lincoln had contemplated such a measure for loyal border states abolishing slavery; such payments were part of a law ending it in D.C. in 1862.

Some enslavers would later claim they voted for the Constitution based on that expectation. To document their losses, the state ordered a census of all enslaved people by county and owner as of Nov. 1, 1864. There was no discussion of compensating the formerly enslaved people for their unpaid labor.

Thus was the stage set for the referendum scheduled for Oct. 12, with polls open for two days. A special train to Baltimore was arranged for Washington Navy Yard workers, who were paid “several days in advance, so that they could enjoy the privilege of going home to vote,” the Washington Evening Star reported. The 9 p.m. train on Oct. 11 was said to carry more than 1,000 passengers. A committee also bought tickets for those in need.

Soldiers — the vast majority serving in Virginia — voted at the quarters of the commanding officer from 8 a.m. to 6 p.m. for five days, according to historian Charles Wagandt. Commissioned officers acted as election judges.

The initial count gave opponents of emancipation a 2,000-vote majority, with Montgomery voters 3 to 1 and Prince George’s voters 9 to 1 against ratification. A proslavery newspaper proclaimed: “MARYLAND REDEEMED! THE NEGRO-ROBBING CONSTITUTION DEFEATED! THE DEATH KNELL OF ABOLITIONISM!”

But the apparent majority dwindled as the absentee ballots trickled in, with 2,633 for and 263 against. Many of the absentee ballots were slips of paper that said simply “For the Constitution“ or “Against the Constitution.”

The 25,000-some Marylanders supporting or fighting for the Confederacy who would not sign loyalty oaths were barred from voting. Lawsuits ensued on various grounds and lost.

The final tally: 30,174 for, 29,799 against. “We believe we can assure our readers that the new Constitution is at last safe, beyond all danger of rejection,” said the Star, “and that they can rejoice over Maryland as Free State, finally and forever redeemed from the curse of slavery.”

There were celebrations in Baltimore, Washington and Philadelphia. On Nov. 26, the Christian Recorder reported, there was a “Colored People’s Jubilee” in Philadelphia, and at a Black church assembly “a vote of thanks was returned to the soldiers and citizens of Maryland, for their hearty support of the Union and the president … and also to Governor Bradford and all the leaders and framers of the new Constitution.”

But there was also fear among the emancipated. Some enslavers asked courts to bind newly freed Black children to them as apprentices.

“We never really celebrated being free, because I think there was fear of the treatment, the stealing of the children,” said Janice Hayes-Williams, an Annapolis activist and historian who counts both enslaved and free African Americans on her family tree.

Yet Nov. 1, 1864, remains the key date in the emancipation of those enslaved in Maryland, and, despite all the proclamations and celebrations surrounding Juneteenth, it is still a date that will live in history in the Free State of Maryland, often forgotten but not gone.

In 2013, Gov. Martin O’Malley (D) signed a bill simply recognizing the day but stopping there. A year later, O’Malley signed another bill requiring the governor “annually to proclaim a certain day as Juneteenth National Freedom Day” in Maryland.

Laments Hayes-Williams: “How can you celebrate somebody else’s history and not your own?”

Eugene L. Meyer, a former Washington Post reporter and editor, is the author of “Five for Freedom: The African American Soldiers in John Brown’s Army.”

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