Americans have wrestled in recent years with whether monuments honoring Confederate leaders such as Robert E. Lee and Jefferson Davis are appropriate. I’m sympathetic to those, like New Orleans Mayor Mitch Landrieu, who have concluded some monuments should come down. But in Arcata, Calif., something more pernicious is going on.

Arcata is a Northern California hot spot of trendy leftism that in 1989 prohibited the manufacture or storage of nuclear weapons within city limits. In 2016, Donald Trump won 10% there, 11 votes more than the Green Party candidate. Now the City Council has raised the monument issue to a new level of nuttiness by voting to remove a statute of President William McKinley from the town square.

Mayor Sofia Pereira explained the council’s rationale by asking, “Is there a difference between honoring McKinley and Robert E. Lee?” There is a very big difference between the Confederacy’s commanding general and the 25th U.S. president.

Start with the issue of race. The son of abolitionists, McKinley enlisted as an 18-year-old private at the start of the Civil War not only to save the Union but also to end the moral blight of slavery. He received three battlefield promotions for bravery, ending the war as a major.

As a young lawyer in 1867, McKinley worked hard to pass an Ohio constitutional amendment protecting black voting rights. Elected to Congress in 1876, he was a staunch advocate of federal civil-rights protections, and as resolutions chairman at the 1884 and 1888 Republican national conventions he ensured that the GOP platform supported such measures. McKinley was the first presidential candidate to appear before black audiences while seeking the nomination in 1896, and he appointed a record number of blacks to federal positions.

McKinley also took on anti-Catholic bigotry, defying America’s largest pressure group, the American Protective Association, when it insisted during his Ohio governorship that he fire Catholic state workers. When the group labeled McKinley the only unacceptable Republican presidential candidate in 1896, he responded that he would not “countenance any abridgement of the constitutional guarantees of religious freedom.”

Moreover, McKinley welcomed the influx of immigrants then coming to America, scandalizing the GOP’s Anglo-Saxon Protestant leadership by inviting groups of foreign-born workers to visit his Canton, Ohio, home during his campaign.

Chris Peters, head of the Arcata group calling for the statute’s removal, blames McKinley for “settler colonialism” that “savaged, raped and killed” Native Americans. Ted Hernandez, chairman of the local Wiyot Indian Tribe, agrees, asking: “Why do we have this man standing in this square where they used to sell our children?”

Both men should consult calendars. The Indian Wars ended long before McKinley became president in 1897. The Wiyots began losing tribal lands to lumbermen and settlers in the 1850s, and dozens of tribe members were allegedly massacred in 1860 when James Buchanan was president and McKinley a teenager. Wiyot children were not sold into involuntary servitude in Arcata’s square with McKinley’s approval during his presidency....