After the Civil War, Ulysses S. Grant spent four years as head of the United States Army in peacetime. With his defeat of Robert E. Lee and the Confederacy, Grant was the most popular man in the country. As the Civil War ended Grant turned his attention to the Plains in the American West where there were numerous conflicts between white settlers, railroads, and Native Americans that resulted in wars between the Natives and the U.S. military. While the attempted Fenian invasion of Canada and French intervention in Mexico took some of his time, Grant's biggest focus was on Reconstruction of the defeated Southern states. Grant found himself caught between President Andrew Johnson, who wanted leniency to the South and a continuation of the social structure there, and the Radical Republicans in Congress, who wanted harsher punishment to rebel leaders and more government assistance to the freed slaves. Grant preserved his popularity and authority throughout the crisis that culminated in Johnson's impeachment. In 1868, the Republicans nominated Grant for president, and he won easily over his Democratic challenger.

Celebrations and honors

In May 1865, the Union League of Philadelphia purchased the Grants a house in that city, but Grant's work was in Washington. He attempted to commute for a time and return on the weekends, but he and Julia decided to move to Washington. They secured a place in Georgetown Heights, while Grant instructed Elihu Washburne that, politically, his legal residence remained in Galena, Illinois. In the spring of 1865, Grant made an appearance at Cooper Union in New York; the New York Times described the reception for the war hero: "...the enhanced and bewildered multitude trembled with extraordinary delight." Further travels that summer, with repeated enthusiastic receptions, took the Grants to Albany and back to Galena and throughout Illinois and Ohio. On July 25, 1866, Congress promoted Grant to the newly created rank of General of the Army of the United States.

Grant was the most popular man in the country. When Johnson was at loggerheads with the Congress over Reconstruction, he took his case to the people with his infamous "swing around the circle" throughout the country and he sought to capitalize on Grant's popularity by having Grant travel with him. Grant, wishing to appear loyal, agreed to accompany Johnson; however he confided in his wife that he thought Johnson's speeches were a "national disgrace". Grant continued his efforts to appear loyal while not alienating Republican legislators essential to his future. At the same time, Johnson also suspected Grant to be a potential candidate in the 1868 presidential election, and decided to replace Secretary of War Stanton with Grant or Sherman. Grant discussed the matter with Sherman and initially convinced him to avoid the politically troubled president.

Johnson sent Grant on a fact-finding tour of the South after which he filed a report recommending continuation of the Freedmen's Bureau but opposed use of black troops in garrisons which were still needed in the South for protection of both races. He also warned of threats by disaffected poor people, black and white, and recommended that local decision making be entrusted only to "thinking men", by which he was thought to have meant, men of property. In this respect, Grant's initial Reconstruction policy aligned with Johnson's policy of pardoning established southern leaders and restoring them to their positions of power. He joined Johnson in arguing that Congress should allow congressional representatives from the South to be seated.

Mexico and Canada

Grant, as commanding general, immediately had to contend with Maximilian of Mexico and the French army which had taken over Mexico under the authority of Napoleon III. Most Americans felt this to be a violation of the Monroe Doctrine. Johnson told Grant to put military pressure on the French to leave Mexico by sending 50,000 troops to the Texas border under Sheridan. Grant told Sheridan to do whatever it took to get Maximilian to abdicate and the French Army to leave Mexico. Sheridan sent Benito Juárez, the ousted leader of Mexico, 60,000 US rifles to aid in an effort to defeat Maximilian. By 1866, the French Army completely withdrew from Mexico; Maximilian was executed by Juárez in 1867. In a cabinet meeting, Johnson suggested Grant be assigned to the Mexican frontier as a way of removing him from the political mainstream. Grant immediately recognized the nature of this proposal, and refused. As a compromise Grant sent Sherman (now promoted to Lieutenant General) in his place.

After the Civil War, thousands of Irish veterans joined the Fenian Brotherhood with the intention of invading and holding Canada hostage in exchange for Irish independence. In June 1866, Johnson sent Grant to Buffalo, New York, to assess the situation. He ordered the Canada–US border closed to prevent Fenian soldiers from crossing over at Fort Erie and that more weapons be confiscated. In June 1866, the United States Army arrested 700 Fenian troops at Buffalo and the Fenians gave up on their attempt to invade Canada.

Indian Wars Grant, as commanding general, inherited the "Indian Wars" in the western frontiers, especially the Plains, as the United States continued westward expansion. After the Civil War ended in 1865, Grant turned his attention to the neglected American western frontier. One of these Plains wars, known as Red Cloud's War, starting in July 1866, was led by Sioux Chief Red Cloud. To end hostilities, Grant ordered forts on the Powder River to be abandoned and for General William T. Sherman to make a peace treaty with the Sioux. As a result, Red Cloud signed the Fort Laramie Treaty in 1868 successfully negotiated by Sherman.

Grant, Johnson, and Reconstruction

In November 1865, Johnson sent Grant on a fact-finding mission to the South. Grant recommended continuation of a reformed Freedmen's Bureau, which Johnson opposed, but advised against the use of black troops in garrisons, which he believed encouraged an alternative to farm labor. Grant did not believe the people of the South were ready for self-rule, and that both whites and blacks in the South required protection by the federal government. Concerned four years of war led to a diminished respect for civil authorities, Grant concluded the Army should continue their presence to maintain order. He also warned of threats by disaffected poor people, black and white, and recommended that local decision-making be entrusted only to "thinking men of the South" (i.e., white men of property). In this respect, Grant's opinion on Reconstruction aligned with Johnson's policy of restoring former Confederates to their positions of power, arguing that Congress should allow representatives from the South to take their seats. Grant believed that former Confederates should be reenlisted into the U.S. military. He personally intervened on behalf of Lee, who had been indicted for treason along with other Confederate generals, keeping Lee safe from prosecution, saving the nation from opening up old war wounds. In January 1866, Grant authorized the removal of cases against Union officers, to federal courts and the Freedmen's Bureau. On July 25, 1866, Congress promoted Grant to the newly created rank of General of the Army of the United States.

In the elections of 1866, an intraparty fight arose in Maryland, when the mayor of Baltimore, a Radical, appointed Radical police commissioners who would be responsible for managing voter registration. Maryland's governor, a partisan of Johnson, requested that federal troops intervene, which Grant initially considered inappropriate. To provide some manner of response, Grant met as a civilian with the opposing party heads and, with use of the army an implicit threat, was able to facilitate a settlement.

Grant's service as Union General, caused him to join the Republican Party, and forced him to consider African Americans as both humans and soldiers. Johnson, a robust Democrat, sided with white supremacists and openly held racist views, believing blacks were inferior and that the country and government were for "white men". Johnson favored a lenient approach to Reconstruction, calling for an immediate return of the former Confederate states into the Union without any guarantee of African American civil rights. The Radical Republican-controlled Congress opposed the idea and refused to admit Congressmen from the former Confederate states. Congress, over Johnson's vetoes, renewed the Freedmen's Bureau and passed the Civil Rights Act of 1866. With Johnson at war with Congress, Grant and Johnson found themselves in a quiet conflict over Reconstruction enforcement, while Grant as a soldier was determined to remain loyal to his Commander In Chief. Needing Grant's popularity, Johnson took Grant on his "Swing Around the Circle" tour, speaking out against Congressional Reconstruction. Enthusiastic cheering for Grant interrupting Johnson's speeches caused the relationship between Johnson and Grant to cool. Grant believed that Johnson was purposefully agitating conservative opinion to defy Congressional Reconstruction, privately calling Johnson's speeches a "national disgrace". Concerned that Johnson's differences with Congress would cause renewed insurrection, Grant ordered Southern arsenals to ship arms north to prevent their capture by Southern state governments. Having returned to Washington, Johnson attempted to send Grant on a mission to Mexico, but Grant refused to go, believing the President did not have authority to send him on a diplomatic mission.

On March 2, 1867, overriding Johnson's veto, making unprecedented use of the power of the military, Congress passed the first of three Reconstruction Acts, which divided the southern states into five military districts. Transitional state governments in each district were to be led by military governors, to ensure that African Americans' newly granted constitutional and congressional rights were protected. Grant, who was to select the general to govern each district, preferred the will of Congress through the enforcement of congressional Reconstruction, but at the outset opposed the use of the military. Nevertheless, Grant adapted and by complying with the Acts and instructing his subordinates to do likewise, he further alienated Johnson. For example, Grant authorized Sheridan to remove public officials in Louisiana who were against congressional Reconstruction. Sheridan's aggressive methods to register freedmen met with Johnson's disapproval, and the President sought his removal. Grant perceptively stayed the middle course, and recommended a rebuke but not a dismissal. Protecting Grant, Congress passed the Command of the Army Act, attached to an army appropriation bill, preventing his removal or relocation, and forcing Johnson to pass orders through Grant, the general in chief. Republicans gained majorities in all 11 states, and African Americans were elected to Congress and high state offices. Grant hoped that Reconstruction Acts would help pacify the South. The Army conducted new elections for constitutional conventions in the ex-Confederate states. They registered blacks to vote and in many places prevented from voting white men who had supported the Confederacy, as set out in the disenfranchisement clause of the Fourteenth Amendment. Throughout the Reconstruction period, more than 1,500 African Americans were elected to political office, while Grant and the military protected their rights initially by overturning the black codes in 1867. Congressional Reconstruction finally ended with the Compromise of 1877 and the complete withdrawal of military troops from the southern states.

Johnson's impeachment