Certainly, Grant’s administration was tainted by oft-remembered corruption scandals. But Grant was never seriously implicated in any of them, although emboldened Democrats and disloyal Republicans, with the help of a sensationalist press, did their best to make the president appear the villain. (Grant ill-advisedly decided to present a stoic public face instead of fighting back.)

In reality, what fueled the personal defamation of Grant was contempt for his Reconstruction policies, which supposedly sacrificed a prostrate South, as one critic put it, “on the altar of Radicalism.” That he accomplished as much for freed slaves as he did within the constitutional limits of the presidency was remarkable. Without question, his was the most impressive record on civil rights and equality of any president from Lincoln to Lyndon B. Johnson.

After Grant left the presidency in 1877, he was widely hailed as the most famous and admired living American, his alleged transgressions overcome by a fabulously successful two-year world tour. He was still beloved at his death in 1885  a reverence embodied by his monumental tomb in Manhattan, overlooking the Hudson.

But Grant came in for decades of disgraceful posthumous attacks that tore his reputation into tatters. Around 1900, pro-Confederate Southern historians began rewriting the history of the Civil War and cast Grant as a “butcher” during the conflict and a corrupt and vindictive tyrant during his presidency. And the conventional wisdom from the left has relied on the bitter comments of snobs like Henry Adams, who slandered Grant as the avatar of the crass, benighted Gilded Age.

Though much of the public and even some historians haven’t yet heard the news, the vindication of Ulysses S. Grant is well under way. I expect that before too long Grant will be returned to the standing he deserves  not only as the military savior of the Union but as one of the great presidents of his era, and possibly one of the greatest in all American history.

Now, Ronald Reagan also has historic achievements  chiefly, discarding the advice of his hard-right supporters, embracing the Soviet leader, Mikhail Gorbachev, and taking the first important steps toward ending the cold war. On the other hand, his record on domestic affairs  especially his unsubtle winking at pro-segregationist Southerners and his administration’s fiercely reactionary policies on civil rights  was appalling.

To honor Reagan’s genuine achievements by downgrading those of Grant would deepen our chronic historical amnesia about the Civil War and Reconstruction, the central events of the first 250 years of American history, and their legacy of nationalism, freedom and equal rights. It’s hard to imagine that Ronald Reagan, whose modesty was part of his charm, would have approved of such a disgraceful act toward another president from Illinois.