“John Wilkes Booth had been captured by US Marshals in May. Though he challenged his captors to a duel, his request was denied and he was sent to the same prison that Jefferson Davis would later be held in. In August, Booth, Powell, Atzerodt and 12 other conspirators were executed by hanging. Many believe that 9 of the 12 other conspirators were probably only tangentially related to the Calamity and did very little if anything illegal but the nation was mourning.
It is truly important to examine the effect that the Triple Calamity had on the American psyche. Especially the northern psyche. The President being assassinated alone would’ve been a disaster, but the decapitation of the executive branch to the point where one of the three sacred branches of government did not function, was a calamity. There were a couple reforms immediately. The 1865 Succession Act and the subsequent passage of the 14th Amendment moved to ensure there would be no more than an hour of executive incapacitation if something similar were to occur. The line of succession became as follows.
Senate Pro Tempore
Speaker of the House of Representatives
Secretary of State
Secretary of War 
Secretary of the Treasury
Secretary of the Navy
Secretary of the Interior
If and when a new department was created its secretary would be placed in the line of succession by congress to where they believed it should go. (Perhaps the Secretary of Homeland Security shouldn’t be behind the Secretary of Labor and so on.)
The 14th Amendment:
In the case of the removal of the President from office or of his death or resignation, the Vice President shall become President.
In the case of the removal of the President and Vice President from office or of his death or resignation, the Pro Tempore of the Senate shall assume the office of President
In the event that the Pro Tempore of the Senate has assumed the office of President, an emergency election shall be held on the first Tuesday of the next November post the assumption of the Pro Tempore. The special election shall not affect the normal election timetable.
In the case of the removal of the President from office or of his death or resignation and in the case that the next member in the line of succession is incapacitated, said incapacity shall be skipped over in the line of succession to ensure a new President is inaugurated at a quick pace.
The 14th Amendment was passed and ratified relatively quickly.  (Though some radically minded congressmen weren’t happy to see the 14th amendment not be on the matter of civil rights.)”
-From Forty Eight Hours: Two Days Without a President
by Lucy Harlaw, published 1992
GRANT'S FIRST ADMINISTRATION
Vice President: Hannibal Hamlin
Secretary of State: Frederick Seward
Secretary of the Treasury: Edwin D. Morgan
Secretary of War: Edwin Stanton (until January 1868), John Schofield
Attorney General: Benjamin Wade
Postmaster General: William Dennison Jr. (Until February 1867), John Creswell
Secretary of the Navy: David Farragut
Secretary of the Interior: John P. Usher (Until June 1867), Jacob D. Cox
“After President Grant assumed the Office of the Presidency on March 4, 1866, he and a friendly congress got to work laying out a proper plan. President Foster had left behind some ideas of his own but they were mostly put to the side and seen as far too moderate. It was universally agreed upon by Grant’s administration that reconstruction ought to be started off with a real bang. Something people would remember for many, many years to come. Benjamin Wade and the Justice Department were asked by President Grant to set their plans into motion. (Some believe that Wade's position as Attorney General was pre-selected by the Speaker of the House...) They were prepared to put the whole war on trial. That said they wouldn’t put any generals on trial. (Except for John Breckinridge the Secretary of War for the CSA and some really nasty cases out west.) President Grant instructed the DoJ not to move forward with cases against people like Lee, Longstreet, Early and Forrest. Grant only wanted to see the politicians and aristocrats go to trial.
This wasn’t because Grant admired people like Nathan Bedford Forrest. It was because Grant thought it would be far more unpopular among confederate veterans to put these men on trial. He understood that while they would be mad to see their former president on trial, they would kill a man to see their very own Moss Robert go on the stand. Even in 1866 some bands of criminals continued to claim the war was not over. Grant didn’t want to see their numbers grow.
United States v Davis was among the largest of a series of court cases known as Union v Confederate cases. In truth, most of the trials were the same (and were lumped together by the Supreme Court) thus for the purposes of this chapter, I’ll focus on Davis.
First off, what was Davis actually indicted for? Conspiracy against the United States, Treason, Mistreatment of Prisoners of War and controversially Conspiracy to Kidnap or Kill the President of the United States. Quite the hefty list of crimes. While President Grant never directly commented on any of the Union v Confederate cases, we know that he was heavily involved in the trials. The actual trial was long and heavily debated over by scholars. Some believed that they were giving Confederate leaders unnecessary platforms while others believed that secession was legal. While scholars debated the actual citizens of the country were pretty uniform. Most northerners wanted to see Davis hung. Conspiracy theorists had run rampant with the story that Davis aided or abetted John Wilkes Booth.
The trial was truly the one of the century. It was held in Washington DC from June to August of 1866. The prosecution had a mountain of evidence and witnesses. Some very high profile witnesses such as Ambrose Burnside, James Longstreet, William Tecumseh Sherman and Edwin Stanton. Mixed in were average soldiers, former slaves and confederates who took plea deals. Davis and his legal team used one primary defense throughout the trial. In 1861, secession was legal. So firstly, any crime Davis committed in the CSA couldn’t be tried in the USA and secondly, it was the Lincoln administration that committed a crime by provoking the Confederate States, a sovereign nation. This led to a whole week of arguing about Fort Sumter and the months before. The prosecution also tried to frame Davis for the Triple Calamity. Davis called this insane. Unfortunately, these sections of the trial are generally restricted to the public. We do know that the prosecution admitted evidence of a telegram that Davis sent to General Breckinridge where he expressed great joy to hear the news. He also expressed that “the beast Stanton” should've been killed as well. . This was a bombshell. The defense argued that the telegram proved nothing and that there was plenty of reasonable doubt that Davis ordered the Calamity…
…When the jury finally returned, Jefferson Davis was found guilty on all counts but one. Conspiracy to Kidnap or Kill the President of the United States. (This has spawned endless conspiracy theories.) The Judge sentenced Davis to death by hanging. Over the summer of 1866 the Federal Government did not lose one of the Union v Confederate cases. All the men indicted were sentenced to death. They also all appealed to higher courts. In December 1866, all the Union v Confederate cases were accepted by the Supreme Court. The defense made the argument that the trial was invalid as secession was legal and thus they could only be tried in a Confederate Court. The prosecution argued that no state had the right to leave the union in 1861 or 1866 and thus the trials were valid and these men ought to be hanged.
This landmark case ended up being 7-2 in favor of the federal government. I want to quickly go over each justice.
Justice Wayne- A man from Georgia but a staunch unionist, Wayne actually agreed with the idea that the Confederacy illegally seceded from the Union. However, he held a strong belief that the Confederate officials shouldn’t have been prosecuted and ruled in the favor of the Confederates.
Justice Nelson- Nelson was an old school justice appointed by President Tyler. He disagreed with the death sentence for the confederates but believed that the confederate secession was illegal. It was for that reason he ruled in favor of the Union, believing it was not his business to overturn a legal Judges’ opinion.
Justice Clifford- Clifford wrote the dissenting opinion. He was already somewhat suspicious of President Lincoln’s handling of the war. Though he didn’t entirely agree that the Confederacy legally left the union, he also believed it was federal overreach to prosecute their leaders.
Justice Grier- Grier was a Polk appointee and a democrat. Yet he ruled in favor of the union with very little reservations. He was deeply affected by the loss of Lincoln, Johnson and Seward. He thought that the country could not heal if traitors went back to their homes scot free. He ruled for the Union.
Justices Swayne, Miller, Davis, Field and Chief Justice Chase- All of these men were appointees of Abraham Lincoln and they all ruled in favor of the Union. The Chief Justice wrote the majority opinion.
On New Year’s Day 1867, Jefferson Davis, Alexander Stephens, John Breckinridge and fifteen other confederate officials were hanged. The same day in New Orleans, a protest turned into a riot. Five freedmen, ten “carpetbaggers” and one Union Solider were lynched. The mob killed the same amount of people as the executed Confederates. New Orleans was placed under Martial law for two weeks as Union Soldiers occupied the city. When news reached the North of the “New Orleans Massacre” (along with numerous other lynchings throughout the south on New Years day), the already boiling anger exploded. President Grant and every member of congress knew that to the people, reconstruction was not going far enough. Not only that but the 1866 midterms had opened up a huge influx of “radical republicans”...
-From Resentment in Dixie
By Peter Barnett, published 1927
(The Senate remains roughly the same as OTL. The House however sees an extra ten seats and a even larger voter share)
: Some of you might notice that the Secretary of the Treasury is ahead of the Secretary of War in the line of succession OTL, I know. Congress changed this ITL believing the SoW should be ahead of the SoT.
: This is a different 14th Amendment. The OTL 14th Amendment will be the 15th and the OTL 15th will be the 16th. The 25th Amendment just showed up early.
: Jefferson Davis wrote a telegraph to John Breckinridge in our timeline as well. In it, he said the job was not finished and said he wished Johnson and Stanton were killed. ITL one of Davis’ hopes is realized.
The Chase Court