When the American civil war started in 1861, was there some sort of declaration or nation-wide announcement that would let everyone know the country was in the midst of a civil war? If not, would normal citizens have even known what was going on?
Along those same lines, is it possible we are already in what future historians will call a civil war? We've already had the battle of Portland, the battle of Kenosha, the battle of Minneapolis, etc. Everyone keeps saying we're "on the brink" of a civil war, but is it possible the civil war has already started but we just can't see it because we're in it?
The U.S. Civil War began when Southern forces fired on federal troops stationed at Fort Sumter in Charleston, South Carolina in April 1861. The general public was quickly informed of this event by newspapers across the county which carried headlines that said things like "WAR BEGUN! The South Strikes the First Blow!" [1]
The country had been bracing for the start of a possible civil war for months. In his First Inaugural Address on March 4, 1861 - about five weeks before the attack on Fort Sumter - President Lincoln addressed the possibility of civil war head on. He said:
In your hands, my dissatisfied fellow-countrymen, and not in mine, is the momentous issue of civil war. The Government will not assail you. You can have no conflict without being yourselves the aggressors. You have no oath registered in heaven to destroy the Government, while I shall have the most solemn one to "preserve, protect, and defend it." [2]
It would have been hard for the average person to be unaware that the war had begun. Within days of the attack on Fort Sumter, President Lincoln issued a call for 75,000 volunteers to fight against the Southern rebellion. This news also went out in newspapers across the country. If anyone was unaware of the situation, though would need to be actively avoiding any and all news. After Fort Sumter, it was clear even at the time that the country had crossed into a new era, distinct from the unrest and escalating tensions of the preceding months.
Though I'm reluctant to speculate too much on the present situation, I will briefly address the second part of your question. While there have certainly been clashes in cities across the U.S. in the last few months, it might be worth considering the scale of these clashes compared to a Civil War battle. Here's just one example - the First Battle of Bull Run, the first major battle of the war, saw about 28,000 Union troops face off against a Confederate force of over 32,000. [3] Including both sides, this battle saw 847 men killed, over 2,700 wounded, and over 1,300 missing or captured. [3] While recent clashes in the United States have certainly resulted in injuries and death - and any loss of life is a tragedy - no conflict in recent American history compares to the scale of the U.S. Civil War.
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[1] Boston Evening Transcript, April 13, 1861: https://www.pbs.org/wgbh/aia/part4/4h1531.html
[2] Abraham Lincoln, First Inaugural Address, March 4, 1861: https://avalon.law.yale.edu/19th_century/lincoln1.asp
[3] American Battlefield Trust, "Bull Run/First Manassas": https://www.battlefields.org/learn/civil-war/battles/bull-run