You realize that the question you pose could be answered by writing a book, so let's start here:
The death of President Lincoln turned out to be the probably greatest misfortune to the South. Initially most of the governors from the seceded States attempted to convene their legislatures and take steps for their restoration to the Union. They did this believing that the American principle of government would be respected and that their prompt proceedings would be favored as the constitutional plan of restoration. They also did this also believing it absolutely necessary to preserve civil government, and to show by legislative enactment complete submission by repealing their ordinances of secession.
However, after the collapse of the Confederacy martial law was imposed on the South. General Wilson, of the United States army in Georgia set the example others would follow. When the Georgia legislature met he stated: "Neither the legislature nor any other political body will be permitted to assemble under the call of the rebel State authorities." The spirit of this order was then carried out in every former Confederate state. The existing civil governments were ignored everywhere, and military rule was inaugurated. The only recognized government was that of the local military officers, their appointees and those under their direct supervision. After military law was established in North Carolina the legislature authorized the governor to proclaim martial law in every county and to arrest and try all accused persons by court-martial rather than judicial law. The State militias in every former Confederate state were composed mainly of freed slaves that were used to enforce the biased laws enacted by state legislatures that often times were even more radical than Congress and the military. Thus approximately 4,000,000 slaves were suddenly enfranchised, with no education or preliminary training, to fit them for their great responsibility. Not knowing what to expect many prominent Southerners and former military officers fled to foreign nations.
As mentioned, under martial law many regular Army officers were appointed to state offices and the governors of Texas and Alabama were actually removed from office. All judges held their places by sufferance. State Superior court judges were summarily ousted from the bench. The same was true of county officers, and mayors and aldermen of cities. Citizens were arrested, and the only authority given was that of the soldiers who made the arrests. Citizens were confined under false and malicious charges urged by irresponsible parties. Two thousand Federal arrests were made in Louisiana alone. And, when the people of a State voiced their opinion not to comply with these severe conditions new acts of legislation were passed, imposing still more stringent conditions.
In the instances of Alabama and Arkansas the US Congress adopted a state constitution without the consent of the people and the states refused to ratify them. Alabama public offices were held by corrupt political appointees and illiterate slaves. The same rule was followed in the county and local offices in every State and municipality.
The legislature of Alabama sat nearly an entire year without enacting any legislation. As soon as it got down to business, it increased state aid to railroads by authorizing endorsements to the extent of $16,000 per mile. Bribery and corruption were rampant. Only one railroad was completed. Five others had track laid but only for a few miles and then abandoned. Fraudulent bonds were issued and bond brokers and railroad schemers conspired to rob the State of many millions of dollars. The legislature also authorized cities, towns, and counties to issue bonds to railroad builders, and many were fleeced, as these same organizations were controlled by the same element elected in the same way as was the legislature. Alabama became insolvent, and Governor Lewis, Republican, said to the legislature that he could not sell for money any of the State bonds. The State debt had grown to the enormous sum of $25,500,000, not including county and city debts.
In North Carolina the treasury was also robbed and the school funds were stolen to pay per diems. The educational investments in securities were sold out at nearly one third their value to the Republican treasurer for himself and his associates. In less than four months, this legislature authorized a State debt of over $25,000,000 in bonds, in addition to $16,000,000 for various minor schemes. The entire debt imposed by reconstruction on North Carolina exceeded $38,000,000. Yet not a mile of railroad was built, although $14,000,000 in bonds were actually issued for this. Not a child, white or black, was educated for two years; not a public building erected, no State improvements were made anywhere.
As another example at the end of the war the average cost of running the South Carolina legislature was approximately $20,000. For the six years following the average annual expense increased to $320,000 [these are 1860s dollars]. Total legislative expenses for the six year period exceeded $2,000,000. The total public debt for South Carolina at the beginning of reconstruction was less than $1,000,000. By 1872 it had escalated to $17,500,000. South Carolina was unable to pay off these debts until the late 1970s. The treasury of South Carolina was so thoroughly gutted there was nothing left to steal. Governor Chamberlain, a Republican, said that when he entered on his duties as governor, "two hundred trial justices were holding office by executive appointment, who could neither read nor write the English language."
In Florida, property decreased in value 45 per cent during eight years of reconstruction, from 1867 to 1875.
In Mississippi, 6,400,000 acres of land were forfeited to the State in payment of excessive taxation, and large amounts were collected as taxes and squandered.
In Louisiana, New Orleans city property decreased in value $58,104,864 in eight years. County property decreased more than one-half, or from $99,266,839 to $47,141,690. One hundred and forty millions of dollars were squandered with nothing to show for it; State debt increased more than $40,000,000; city property depreciated 40 per cent, county property 50 per cent.
Two-thirds of the wealth of the Southern people had been swept away, and the South was bankrupt. In addition the states were also compelled to repudiate all debts contracted for carrying on the war. In the approximate ten years of reconstruction legislation and government, conducted under carpet-baggers, an additional debt of $300,000,000 was added to the burdens of the people of the South.
For five years after the war, in West Virginia, Mississippi and many other states, including border states, an ex-Confederate was not a citizen, could not hold office, could not practice law, could not sit as a juror, could not teach school, could not sue in the courts, could not make a defense for charges brought during his absence, could not be administrator or executor.
The Union Leagues were instituted by northern whites to impose their will on freed slaves. The leagues taught that the white men of the South were enemies of the freed slaves, and it excited them to commit acts of disorder and create interference in every way with the whites. The poor illiterate ex-slaves could not withstand the strong will of the whites from the North, who were controlling them, against all advice and friendly appeal from Southern whites. Friction, conflict, disorder between whites and blacks were incited to prolong the important and lucrative offices held by the carpetbaggers. It was the stock in trade of the Republicans in the South to keep up the vindictive and hostile legislation of Congress, and it is needless to say that members of the league had the ear of Congress. Regretfully this resulted in the rise of the Klan and racial misunderstandings that exist to this very day.
Tell me, where would you start making changes?