By now you’ve probably dismounted from your high horse.

After all, President Obama reminded us that while it is bad that the Islamic State (which apparently isn’t Islamic, “whatever ideology they’re operating off of”) is beheading people and burning them alive in 2015, Christians (who were obviously Christian) also did very bad things in 1215.

If you didn’t learn this presidential history lesson, The Atlantic’s Ta-Nehisi Coates is here to offer extra help after class. He points out that Christianity was often invoked in defense of slavery, segregation and white supremacy for a large part of American history.

“The interest in power is almost always accompanied by the need to sanctify that power,” Coates theorizes. “That is what the Muslims terrorists in ISIS are seeking to do today, and that is what Christian enslavers and Christian terrorists did for the lion’s share of American history.”

Very well, then. The next time some Republican says dumb and ugly things about race, our Democratic friends will apply the same logic and say something like the following:

Lest we get on our high horse and think this is unique to some other party, remember that from its founding until the 1960s, people committed terrible deeds in the name of the Democratic Party. In our own party, slavery and Jim Crow all too often were justified in the Democratic platform.

Confederate General Nathan Bedford Forrest, possibly the first grand dragon of the Ku Klux Klan, spoke at the 1868 Democratic National Convention. Most Klansmen were Democrats. The party refused to condemn the Klan as late as its 1924 convention, a gathering wags called “the Klanbake.”

Woodrow Wilson, a progressive Democrat, was a white supremacist who re-segregated the federal workforce. Segregationists were part of the New Deal coalition and were running mates even to liberal Democratic presidential candidates into the 1950s. In 1956, 99 of the 101 politicians who signed the racist “Southern Manifesto” were Democrats.

The major civil rights legislation of the 1950s and 1960s were supported by a lower percentage of Democratic members of Congress than Republicans. This included J. William Fulbright, who was a mentor to Bill Clinton, Al Gore Sr., who was father of the future vice president, and Robert Byrd, an ex-Klansmen who was the Senate Democratic floor leader until 1989 and an elected Democrat until his death in 2010.

George Wallace, Bull Connor and Lester Maddox were all Democrats… By now you get the point.

We don’t need to ask whether liberals think any of this history is relevant to the Democratic Party today. They’ve told us repeatedly.

When then-conservative Bruce Bartlett wrote a book about the Democrats’ past racism, the Washington Monthly’s Steve Benen dismissed it as “cheap and silly.”

“If history ended in 1965,” Benen concluded, “Bartlett may have a legitimate point.”

Or as Matthew Yglesias put it, “that was all quite a long time ago.”

Not longer ago than the history Obama and Coates cite in comparing Christian supporters of slavery and segregation in the 19th and 20th centuries to ISIS today. (Coates curiously downplays the extent to which Christianity also played a role in abolishing slavery and segregation.)

It’s all much more recent than the Crusades or the Inquisition.

If we’re talking about Christians or Americans, there is a direct link between the distant past and today. If we’re talking about Democrats, it’s all ancient history.

It’s almost like saying that bringing up the weather to argue against global warming is stupid but bringing up the weather to argue for it is really smart and sophisticated.

All analogies break down somewhere. There’s obviously less continuity between the Democratic platforms of 1860 and 2012 than Christian doctrines from the early church to today.

Most liberals would say that whatever the sins of past Democrats, what’s relevant is where the party stands today. The same is true for the president’s history lesson: whatever sins have historically been committed in the name of Christianity, ISIS is setting people on fire right now.

The United States abolished slavery in 1865. ISIS still practices it.

Yes, we should resist the urge to dehumanize or make enemies of all Muslims. The Jordanian pilot brutally murdered by ISIS was a Muslim. His countrymen who are risking their lives in the fight against ISIS are Muslims.

But we should also acknowledge that some of the things jihadists fight for, such as the death penalty for apostates, have much more popular support in the contemporary Muslim world than Timothy McVeigh, the Olympic bomber, the Ku Klux Klan or abortion clinic bombers enjoy in the United States.

A 2013 Pew Research Center poll found that Muslims themselves often worry more about Muslim extremism than other forms of religious extremism. As noted above, the victims of Muslim extremists are often Muslims.

And while majorities throughout the Muslim world told Pew they rejected violence, the minorities were not trivial in number.

In his “Evil Empire” speech, Ronald Reagan acknowledged America’s sin of racism while condemning the Soviet system. Nobody mistook where he stood.

Our current president should have taken a similar approach. If history ended in 1215, Obama may have a legitimate point.

W. James Antle III is managing editor of The Daily Caller and author of the book Devouring Freedom: Can Big Government Ever Be Stopped? Follow him on Twitter.