From the time of the Gettysburg Address, "Four Score and Seven Years ago" refers to 1776, when the Declaration of Independence was put forth.
Lincoln is calling forth the memory of when those political bonds were being dissolved.
Rather silly when you are doing your utmost to *STOP* people from dissolving similar political bonds.
The separation from the British monarchy was the creation of a form of self-government "conceived in Liberty, and dedicated to the proposition that all men are created equal."
In 1863, that form of government, the only one in the world, was threatened with "perish[ing] from the earth" by the unilateral secession of the Confederate states. The preservation of "government of the people, by the people, for the people," was the issue. That meant the preservation of the Constitution and the compact it represented.
The political bonds in the two situations were by no means similar.