A war fought within the United States of America from 1860 to 1865 which killed more US people than any other conflict that nation has been involved. It came out of a range of internal traditions, most notably over slavery (claims of states’ rights as a cause are diminished by the prominent mention of slavery in the various declarations issued by the pro-slavery southern states at the state of the conflict).
The conflict saw developments in the use of military weapons and inventions such as railways (and photography), and included a wide range of human rights abuses (especially against people of colour, but also generally against civilians) but also advances such as the 13th Amendment banning slavery.
The anti-slavery northern states are generally considered to have been hindered by poor generals in the early stages of the war. US Grant eventually led the forces of the northern states to a victory noted by its magnanimity towards the forces of the defeated southern states, and later became a President who continued actions in support of human rights (albeit with flaws and scandals).
A notable, perhaps exemplary, role was played the US President Abraham Lincoln, with speeches that promoted unity. Lincoln was assassinated by disgruntled southerners just after the war, which resulted in transfer of power to the destructive (of human rights) Johnson.
Grant undid a portion of that destruction, but the tensions resulting from the conflict (and perhaps especially from the assassination of Lincoln, who was most likely to pull the still divided nation together) last to this day (despite the efforts of people such as Martin Luther King, Jr. and the 1960s President Johnson, whose desire for civil reform was undone by the Viêt Nám War) and can be seen the the Black Lives Matter protests and the resultant white supremacist backlash.
For more on this topic (written by experts, rather than me), see :
- https://en.wikipedia.org/w/index.php?title=American_Civil_War&oldid=1057031718;
- https://www.britannica.com/event/American-Civil-War;
- https://www.battlefields.org/learn/articles/brief-overview-american-civil-war;
- “Robert E. Lee and Me: A Southerner's Reckoning with the Myth of the Lost Cause” by Ty Seidule https://smile.amazon.com/gp/product/B08BKJJJG8/ref=ppx_yo_dt_b_d_asin_title_o00;
and
- https://www.thoughtco.com/innovations-in-technology-during-the-civil-war-1773744;
- Edward Porter Alexander (https://en.wikipedia.org/w/index.php?title=Edward_Porter_Alexander&oldid=1054650287) “Military Memoirs of a Confederate” (1907) - https://archive.org/details/militarymemoirso00alex;
- US Grant (https://en.wikipedia.org/w/index.php?title=Ulysses_S._Grant&oldid=1056611282, https://www.britannica.com/biography/Ulysses-S-Grant, and “Grant” by Ron Chernow at https://smile.amazon.com/Grant-Ron-Chernow-ebook/dp/B073WHBH8T/ref=tmm_kin_swatch_0) - “Personal Memoirs of U.S. Grant” - https://en.wikipedia.org/w/index.php?title=Personal_Memoirs_of_U._S._Grant&oldid=1035843760 and https://www.gutenberg.org/files/4367/4367-h/4367-h.htm;
- Abraham Lincoln - see https://en.wikipedia.org/w/index.php?title=Abraham_Lincoln&oldid=1056198539, https://www.britannica.com/biography/Abraham-Lincoln, https://www.whitehouse.gov/about-the-white-house/presidents/abraham-lincoln/, https://en.wikipedia.org/w/index.php?title=Lincoln_(film)&oldid=1056566570, https://www.nps.gov/liho/learn/historyculture/speeches.htm, https://en.wikipedia.org/w/index.php?title=Assassination_of_Abraham_Lincoln&oldid=1056059296, and https://gnwmythr.blogspot.com/2015/08/post-no-740-can-one-person-make.html;
- https://en.wikipedia.org/w/index.php?title=Andrew_Johnson&oldid=1056963179#Historical_reputation_and_legacy;
- https://en.wikipedia.org/w/index.php?title=Presidency_of_Lyndon_B._Johnson&oldid=1055182605#Historical_reputation, https://en.wikipedia.org/w/index.php?title=War_on_poverty&oldid=1053301072; https://en.wikipedia.org/w/index.php?title=Civil_Rights_Act_of_1964&oldid=1056640580, and https://en.wikipedia.org/w/index.php?title=All_the_Way_(film)&oldid=1039874473;
- https://blacklivesmatter.com/, https://en.wikipedia.org/w/index.php?title=Black_Lives_Matter&oldid=1057016397, https://www.britannica.com/topic/Black-Lives-Matter, and https://www.weforum.org/agenda/2016/08/black-lives-matter-movement-explained/;
- https://www.merriam-webster.com/dictionary/white%20supremacist, https://en.wikipedia.org/w/index.php?title=White_supremacy&oldid=1055587444, https://www.adl.org/education/resources/reports/state-of-white-supremacy, https://www.lowyinstitute.org/the-interpreter/it-s-not-ok-white-supremacy-and-australia-s-security-services, and “A Field Guide to White Supremacy” by Kathleen Below and Ramon A. Gutierrez - on Amazon at https://smile.amazon.com/Field-Guide-White-Supremacy-ebook/dp/B09CKVF85B/ref=sr_1_1.