(Kaiserreich) When did the US victory on civil war became inevitable?

[Sierra]

I would offer keeping California in the Union, and retaining the Canal. Without the Navy interdicting enemy trade, and a secure population, industrial, and agricultural base out of reach of the CSA and AUS, the war would quite likely have gone much differently.

 

[Ice34]

The Fed's greatest defeat was likely the envelopment at St. Louis mentioned earlier. Losing Bradley and roughly 12000 soldiers so early shook the Federal military heavily. The tragedy deeply demoralized the 2nd army group and contributed to the ease in which they were pushed out of Missouri by the CSA. The impact his death had on the leadership both in the Federal military and the Unionist military can be seen quite clearly. Both Eisenhower and Patton were devastated at his death and the attitude they took reflected this. Patton's already unyielding nature and hatred for syndicalism somehow became more intense. He pushed his army harder leading to the breakthrough in northern Virginia resulting in Washington falling to the Unionists and Patton coming within sight of Philadelphia before his advance was ground to a halt. Eisenhower became more ruthless as well: employing scorched earth in the prairies of Kansas and Nebraska, conducting asymmetrical warfare in Missouri, and later on in the war conducting the Burning of Chicago.

Other candidates would be the failed Florida Campaign or the Battle of Norfolk.

 

[Kaze]

When I have to march through the whole length of Russia in order to achieve victory conditions. Somehow every time I play the game, except that one time I played South America, I am forced to march through the whole length of Russia in order to win - sometimes I have to do it twice fighting through the world's worst infrastructure watching my troops take attrition.
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As for when it became an end, I would say when Louisiana is lost.