If the Cotton States shall become satisfied that they can do better out of the Union than in it, we insist on letting them go in peace. The right to secede may be a revolutionary one, but it exists nevertheless ... And whenever a considerable section of our Union shall deliberately resolve to go out, we shall resist all coercive measures designed to keep it in. We hope never to live in a republic whereof one section is pinned to the residue by bayonets.
Similar editorials appeared through January 1861, after which Tribune editorials took a hard line on the South, opposing concessions.[69] Williams concludes that "for a brief moment, Horace Greeley had believed that peaceful secession might be a form of freedom preferable to civil war".[70] This brief flirtation with disunion would have consequences for Greeleyit was used against him by his opponents when he ran for president in 1872.
In the days leading up to Lincoln's inauguration, the Tribune headed its editorial columns each day, in large capital letters: "No compromise!/No concession to traitors!/The Constitution as it is!" Greeley attended the inauguration, sitting close to Senator Douglas, as the Tribune hailed the beginning of Lincoln's presidency. When southern forces attacked Fort Sumter, the Tribune regretted the loss of the fort, but applauded the fact that war to subdue the rebels, who formed the Confederate States of America, would now take place. The paper criticized Lincoln for not being quick to use force.
Through the spring and early summer of 1861, Greeley and the Tribune beat the drum for a Union attack. "On to Richmond", a phrase coined by a Tribune stringer, became the watchword of the newspaper as Greeley urged the occupation of the rebel capital of Richmond before the Confederate Congress could meet on July 20. In part because of the public pressure, Lincoln sent the half-trained Union Army into the field at the First Battle of Manassas in mid-July where it was soundly beaten. The defeat threw Greeley into despair, and he may have suffered a nervous breakdown.[
As did many others following Fort Sumter.
In this context, let's review again Doughfaced Northern Democrat Buchanan's response:
"He also wrote a letter to his fellow Pennsylvania Democrats, urging them to 'join the many thousands of brave & patriotic volunteers who are already in the field'.[80] "
“In the days leading up to Lincoln’s inauguration, the Tribune headed its editorial columns each day, in large capital letters: “No compromise!/No concession to traitors!/The Constitution as it is!””
That is an interesting citation - northern newspapers demanding “The Constitution as it is!”
The United States Constitution at that time enshrined slavery.
Your citation seems to undercut those today that publish opinions saying the war was “all about slavery” and that Lincoln “fought to free the slaves.”