From Grant, by Ron Chernow (Penguin, 2018), Kindle pp. 570-571, 580-581:
Grant returned to a capital preoccupied with the civil rights bill introduced by Radical Republicans to nullify Black Codes in the South that prevented freedmen from owning property, making contracts, and filing lawsuits. Though silent on voting rights, the bill sought to bring the full blessings of citizenship to anyone born in the United States, including blacks, protecting them by the “full and equal benefit of all laws.” (Native Americans were excluded.) This landmark legislation defined citizenship rights in a new manner that made the federal government, not the states, the guarantor of basic liberties.
On March 27, Andrew Johnson vetoed the bill, denouncing it for trespassing on states’ rights. Instead of viewing it as a brave attempt to remedy historic injustice, he denigrated it for surpassing anything the federal government “has ever provided for the white race.” Perversely, he interpreted it as a case of reverse discrimination “made to operate in favor of the colored and against the white race.” He heaped further insults on the black community by stating that immigrants had superior claims to American citizenship because they better understood “the nature and character of our institutions.” The veto was a reckless move by Johnson, the original bill having passed both houses by overwhelming margins. In a stunning rebuke, Congress dealt a resounding defeat to Johnson by overriding his veto. Johnson had damaged his standing, leading even moderate Republicans to distance themselves from him. “The feud between Johnson and the ‘Radicals’ grows more and more deadly every day,” observed George Templeton Strong, “and threatens grave public mischief.”
Grant was caught in the dispute as both sides worked hard to lay claim to his incomparable prestige. Thinking it improper for army officers to take public stands on legislation, Grant had kept a punctilious silence on the civil rights bill, but Johnson was bent on enlisting his support whether he liked it or not. When Grant threw a glittering soiree at 205 I Street, President Johnson ventured outside the White House to stand between Ulysses and Julia Grant on the receiving line, and Radical Republicans were taken aback by his presence.
Grant’s team of commanders in the South enforced the new Civil Rights Act. General Daniel Sickles abolished South Carolina’s Black Code, stating that “all laws shall be applicable alike to all inhabitants,” while General Alfred Terry barred Virginia’s vagrancy law as an effort to restore “slavery in all but its name.” A backlash arose among white southerners, producing stepped-up vigilante activity as robed, hooded figures beat and murdered blacks. White northern teachers working with the Freedmen’s Bureau faced death threats and black schools and churches were burned with impunity in North Carolina, Mississippi, and Alabama. Grant continued to present Johnson with statistics documenting racially motivated violence against blacks and added two new categories of coercion: driving off blacks “without compensation for labor” and “retaining freedmen without compensation.”
On September 22, Grant performed an act that spoke volumes about his secret sympathies: he quietly ordered the chief of ordnance, General Alexander Dyer, to empty surplus weapons from five southern arsenals and send most of their small arms to New York Harbor. He also spurned a request from Virginia to furnish ten thousand weapons for white militias to confront a supposedly better armed black population. In addition, he opposed rearming former Confederate states. Writing confidentially to Sheridan, Grant warned that few people who fought for the North exerted any influence over the pro-southern president. Johnson, he feared, would declare Congress as a body “illegal, unconstitutional and revolutionary. Commanders in Southern states will have to take great care to see, if a crisis does come, that no armed headway can be made against the Union.” The outside world may have wondered about Grant’s sympathies, but his private statements leave no room for conjecture about his inexorable drift toward Radical Republicanism. Welles later speculated that by fall 1866, Grant “was secretly acting in concert with the Radicals to deceive and beguile the President.” Grant didn’t regard it as deception so much as adhering to bedrock principles, telling Badeau he had “never felt so anxious about the country.”
As it happened, Grant swam in a strong political tide. Johnson’s “swing around the circle” [election campaign tour] was such an indescribable fiasco that Republicans registered stunning gains in the fall elections, winning substantial majorities in both houses of Congress. The election also resoundingly endorsed the Fourteenth Amendment. These electoral gains prompted speculation about whether Johnson would seek by force to block the new Congress from meeting. Taking advantage of their election mandate, Radical Republicans planned to initiate a period of Congressional Reconstruction, helping blacks and white Republicans in the South and supplanting Presidential Reconstruction, with its heavy bias toward southern white Democrats.