The Civil War filled four years with death and destruction. Politicians on both sides vastly underestimated the human carnage from the conflict they were about to ignite. The Union was preserved, but at a cost of 620,000 dead.

The contending leaders suffered grievously for their roles. Abraham Lincoln was assassinated before the last Confederate forces laid down their arms. Jefferson Davis was captured on the run and subjected to punitive imprisonment.

Historian James Swanson nicely juxtaposes the different experiences of the two men, one carried on a funeral train to his burial place while the other was being carried by horse away from the former’s invading forces. Although their lives at the end of the Civil War dramatically diverged, their deaths converged. Explains Mr. Swanson: “Just as April 15, 1865, symbolized to the North more than the death of just one man, so too the death pageant that followed December 6, 1889, was not for Davis alone.”

April 1865 confirmed the destinies of the two wartime leaders. Combat in the West had gone decisively against the South, with Union forces effectively breaking the Confederacy in two in July 1863 by occupying Vicksburg. The North controlled the entire Mississippi River and William Sherman’s army captured Atlanta and advanced to the Atlantic.

But in the East, the two sides spent most of four years battling between Washington and Richmond. Even after Robert E. Lee’s Army of Northern Virginia had been drained of offensive power in the summer of 1864, it continued to protect the city of Petersburg and the Confederate capital of Richmond. As long as Lee’s rugged veterans were in the field, the South retained hope of winning its independence.

On April 2, Lee warned the Confederate government that his lines had been broken and Richmond had to be evacuated. In one of the war’s most dramatic moments, Davis, the Mississippi senator and reluctant secessionist, received Lee’s message while worshipping at St. Paul’s Episcopal Church in Richmond. Davis tarried, hoping for yet another Lee miracle. It was not to be, and that night Davis was forced to begin what became a five-week journey, ending in Irwinville, Ga.

In contrast, Lincoln’s month began in triumph. Once Lee retreated, Richmond became a spoil of war for the North, and Lincoln paid the vanquished city a visit. Unfortunately, the North’s impending victory triggered an embittered John Wilkes Booth to form a conspiracy against top federal officials. Booth shot Lincoln, who died on April 15. In death, Lincoln also began a momentous journey.

Mr. Swanson ably details the parallel trips. Although Davis started out hoping to relocate the government and continue the war, he soon discovered that he was a president in name only. Davis was alive, but the Confederacy was dead.

Davis’ remaining generals did not share his enthusiasm for continuing the fight. His travels turned from fight to flight. Yet Davis and his entourage received a cool reception as they moved south. Local residents did not want to risk the wrath of federal occupiers by opening their homes to the Confederate fugitives.

Lincoln’s journey was different. How to handle his remains was complicated by Mary Lincoln (often unstable in the best of times) and a multicity struggle to become his burial place. Funeral arrangements ended up in the hands of George Harrington, an assistant secretary of the Treasury. On April 21, Lincoln’s body started its circuitous rail trip from Washington to Springfield, Ill. Crowds lined the route through Maryland, Pennsylvania, New Jersey, New York, Ohio and Indiana.

The movement of Lincoln’s body riveted the nation’s attention. Observes Mr. Swanson: “Lincoln’s coffin became a kind of ark of the American Covenant, possessing hidden meanings and mysterious powers. The death pageant was both a civic and a religious event.”

Indeed, it is this process, he argues, that “transfigured Abraham Lincoln from man to myth.” Lincoln’s travel ended on May 3. After the assassination of John F. Kennedy nearly a century later, Jacqueline Kennedy told the U.S. chief of protocol to “Make it like Lincoln’s.”

Davis’ journey ended ignominiously. A Union cavalry detachment happened upon the Davis party encampment early on May 10. Davis spent two years in prison, much of the time in irons. On May 11, 1867, Davis was released pursuant a writ of habeas corpus. He was never brought to trial.

He spent his final years writing a somewhat ponderous memoir and living with his wife, Varina, on the estate of a widowed Mississippi friend. After his death on Dec. 6, 1889, his body also went on a well-watched rail journey. In 1907, a monument to Davis was erected on Richmond’s famed Monument Avenue. Roughly 325,000 people gathered to commemorate his life, more than saw the martyred Lincoln off from Washington.

However, while the Lost Cause lived on, notes Mr. Swanson, “The twentieth century came to belong to Abraham Lincoln, not Jefferson Davis. His eclipse began as early as 1922, with the completion of the Lincoln Memorial.” Symbolic of Davis’ decline was Hurricane Katrina’s destruction of the Beauvoir estate where Davis finished his life. In August 2005, writes Mr. Swanson, “the sanctuary where Jefferson Davis labored to preserve for all time the memory of the Confederacy, its honored dead, and the Lost Cause was, by wind and water, all swept away.”

In Bloody Crimes, James Swanson describes well the twin journeys of Abraham Lincoln and Jefferson Davis. These men were the two most important political figures during the most tragic period of American history. The Civil War offered much pageantry and heroics. But “Bloody Crimes” reminds us that the Civil War was more fundamentally a time of unnecessary and tragic folly.