Needless to say, in issuing an Emancipation Proclamation Lincoln was playing for high stakes indeed.
One of the ways this decision cost Lincoln was militarily. Northern soldiers were ok with fighting to preserve the Union, but freeing the slaves was too much for them. Particularly in the middle states – states like Illinois, Indiana, Ohio that touched the South – thousands of whilte soldiers walked away from the war. One of the most dramatic examples of this took place in April of 1863, four months after the Proclamation went into effect: the entire 109th Illinois Infantry Regiment was arrested for mutiny!
In addition, the fragile bi-partisan support for the war in Congress evaporated like snow in spring. As one irate opponent put it, it was a blasphamy to make equal those whom God Himself had created unequal.
And finally, of course, despite assurances from Republican newspapers that blacks would not flood the North and take away jobs, the Republicans paid a heavy price during the mid-term elections of 1862, which took place just a few weeks following the issuance of the preliminary Emancipation Proclamation.