What were the major problems facing the nation in April 1865? What factors stood in the way of a solution to those problems? Provide examples...

This period from 1865 to 1877 is usually called Reconstruction.

The obvious problem for America in April 1865 is the assassination of a President: Abraham Lincoln was murdered on April 14, 1865. The sudden death of a country's leader can only bring turmoil even in the best of times---and this was certainly not the best of times.

The United States had just emerged from its one and only civil war, the first major war US soldiers had fought in 50 years. One major problem that arose was what to do with these Southern states: They had started part of the US, seceded to form their own Confederacy, and now were occupied by Union troops at the conclusion of the war. The question of how to re-integrate them into the United States loomed large, and raised a number of sub-questions about whether and how much they should be penalized for their rebellion, what sort of reforms they should be required to undertake, what sort of governance the newly re-integrated states should have. After taking office President Andrew Johnson pardoned thousands of Confederate officials (mostly civil servants and minor military officers), while prosecuting the top brass and major political leaders. He also formed the Ten Percent Plan requiring loyalty oaths from ten percent of each Southern state's population. Like most compromises, this angered both sides; the Radical Republicans wanted the South punished more severely and oaths of a majority, while Democrats thought the whole idea of prosecuting Confederate leaders and demanding loyalty oaths was unfair.

The war had caused massive economic devastation, as wars usually do; so another question was also how to rebuild the South and what the new economic structure there should look like.

And of course how can I forget the chief reason the war was fought in the first place: Slavery. (Revisionists will often point to other reasons, and some of these may have contributed, but it is very clear that slavery was the primary point of contention between Northern and Southern states---that "states' rights" in this case largely meant states' rights to have slavery.)

At the conclusion of the war, slavery had just been fully abolished across the United States; so now the question became what to do with all these people who had previously been slaves. Ideally we would provide them with education, give them property to start out with, help them become full citizens of society; but this would be very difficult and expensive to do, and was resisted for other reasons as well. (Funny thing, a lot of the plantation owners were not thrilled about having their land and wealth redistributed to their former slaves! Of course that was precisely what we needed to do, but they fought tooth and nail to prevent it.)

The result of this contention was mixed results; while many former slaves did manage to get educated, find jobs, and make a living, many others were unable to because of barriers placed in their way, including laws discriminating against Black people in many states (and not only Southern states!). A lot of Americans don't know that there was a Civil Rights Act of 1875 which sought to ban racial discrimination in public places---but was largely unenforced and later ruled un-Constitutional by the Supreme Court. (Why? I'm trying to find a better reason than "racism", but it's not easy.)

In 1877, Union troops were ordered to end their occupation of the South and restore local control; this is usually considered the end of Reconstruction.