Sally Kohn is an activist, columnist and television commentator. Follow her on Twitter: @sallykohn . The opinions expressed in this commentary are hers.

(CNN) It's clear that Donald Trump has no idea what Sharia is. Earlier this month, Trump proposed what he described as "extreme vetting" to ban immigrants who "believed Sharia law should supplant American law." But while this irrational fear-mongering might play well to some of his supporters, it is detached from reality.

Perhaps Trump isn't interested in the truth. The rest of us should be, though, because understanding the truth about Islam is the best way to fight extremism within it. The alternative is to misunderstand and misrepresent the majority of the world's 1.6 billion Muslims, the very people who have the greatest stake in the fight. (Remember, the vast majority of victims of Islamic extremist attacks are Muslims.)

So, what exactly is the truth about Sharia, and how does that help us combat extremism? In short, there is a difference between personal, spiritual Sharia and the political incorporation of Sharia into law. And within both, there are progressive interpretations as well as more fundamentalist conservative interpretations. So the word Sharia doesn't mean one thing.

"Every practicing Muslim -- whether traditional or conservative or progressive -- in some way follows Sharia," says Wajahat Ali, a Virginia-based writer and creative director of Affinis Labs . "There's no book called Sharia. You can't rent it. It's subject to human interpretation and is malleable, thus explaining how Muslims have existed for 1,400 years in nearly every society."

Sharia means "the path" in Arabic and basically the spiritual or moral code of Islam. But as Ali notes, "because it's based on subjective interpretation, it's been used and abused by folks with varying agendas."

"Essentially any Muslim who is practicing at any level is following some part of Sharia," agrees Raquel Saraswati, a lesbian feminist Muslim. "I don't drink. I don't go to clubs." She says she also doesn't watch certain music videos.

"I also pray according to the rules and a whole host of other things. So basically I'm engaging with Sharia every single day." Some of Saraswati's gay Muslim friends, she says, are far less observant on a daily basis but might fast for Ramadan, for instance. (As a Jew who eats pork, I get it. Faith can take many different forms.)

Critics of Sharia often miss these nuances, assuming for example that those who practice Sharia believe adulterers should be stoned and gay people thrown off roofs.

And clearly some Muslims believe this and cite "Sharia." But Fred Phelps , founder of the "God Hates Fags" Westboro Baptist Church, also thought gays should be put to death. Death is, after all, mentioned as a punishment for homosexual relations in the Bible. But thankfully, not all Christians follow such beliefs. Remember, Phelps was a Christian, but so was the Rev. Martin Luther King Jr.

But the reality of these flexible concepts doesn't stop many people conflating Sharia with the most extreme interpretations of Islam. Newt Gingrich, for instance, has said that every Muslim in the United States who believes in Sharia "should be deported." In doing so, he seems to demonstrate a fundamental misunderstanding of Sharia, along with Trump and his right-wing allies, by essentially suggesting that any Muslims who want to make Sharia "the official law in their country" are tantamount to violent extremists. This is not only factually wrong but "utterly stupid and childish," says Abdullahi An-Na'im, professor of law at Emory University and author of the important book "Islam and the Secular State."

So what about Muslims who say they want Sharia law? They're not all necessarily extremists, as the anti-Muslim American right has claimed. An-Na'im suggests that what they are really talking about is "Sharia as an ethical normative system underpinning the laws that are enacted through constitutional institutions -- much in the same way that Americans consider Christianity as underpinning American law and culture."

That doesn't necessarily mean following the most violent or severe interpretations of Christianity -- thankfully stoning is not enshrined into US law (although we do execute more people than virtually any other country). But when we talk with pride about our Judeo-Christian values-inspired Constitution, we can understand how Muslims would want the positive moral values in their faith to be an inspiration for secular law.

Sharia law can also mean what it does in England, where Sharia councils in some places hold sway over things such as marriage and divorce for British Muslims. Yet those councils are ultimately -- and rightly -- subject to the secular laws of the state. In fact, the British government has launched a review of the workings and decisions of Sharia councils to ensure they adhere to British law, an inquiry being led by noted Muslim scholar Mona Siddiqui and also advised by two imams. This suggests a potential model for how Sharia can work within the context of secular government and pluralism.

In other words, the version of Sharia implemented by right-wing extremists in ISIS and Saudi Arabia is reprehensible but is not the sole definition of Sharia. Pointing out that there is more than one interpretation of Sharia, and that all Muslims are not violent extremists, is in no way, shape or form meant to defend or excuse countries such as Saudi Arabia and the unjust hatemongers who run them. Their policies toward women, the LGBT community, Christians, Jews and many others are inhumane and unacceptable.

I'm not arguing that we should in any way give Islamic fundamentalists a pass. What I am arguing is that we should intensely focus on the actual problem -- extremist interpretations of Islam advanced by Saudi Arabia and ISIS -- rather than smearing all of Islam and, in the process, alienating the moderate Muslims who are the most important voices in transforming their own faith.

of those who described Fox as their most trusted news source believed this is the true agenda of American Muslims, the same poll showed. And yet it's hard to focus on real solutions when we're so distracted by fear-mongering. According to a 2011 poll , for example, 1 in 3 Americans believed that American Muslims ultimately want to establish Sharia as the law of the land in the United States -- in other words, not just local councils, but overriding the Constitution. Nearly 6 in 10of those who described Fox as their most trusted news source believed this is the true agenda of American Muslims, the same poll showed.

Where do such beliefs -- and fears -- stem from? They result from hearing someone like Gingrich say Sharia "is a mortal threat to the survival of freedom in the United States and in the world as we know it." And people like Michele Bachmann describing Sharia as something that "must be resisted across the United States." What the American people aren't hearing is basic facts about Islam, including about how charitableness is one of the five main pillars of Sharia and how eight Muslim nations have elected women heads of state (something the United States has yet to do).

Islam isn't inherently in conflict with democracy and freedom; fundamentalism is. We must support Muslims and people of faith everywhere who oppose fundamentalism and support democracy, tolerance and pluralism. We must support moderate Muslims, rather than attacking Sharia.

"In the hands of terrorists, Sharia can be developed into a highly threatening, militant notion," Bernard G. Weiss, a scholar of Islam at the University of Utah, told The New York Times in 2011 . "In the hands of a contemporary Muslim thinker writing in the journal Religion and Law, Sharia becomes an essentially pacifist notion."

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Sadly, the fact that there are many interpretations of Sharia, just as there are many interpretations of Jewish and Christian moral codes, gets lost in the weeds of right-wing generalizations and fear-mongering.

Meanwhile, tolerant, democratic, pluralistic Muslims across the United States and around the world -- including, yes, feminist, pro-gay, progressive Muslims -- are following interpretations of their faith that we not only shouldn't sideline but should actively encourage. We should be supporting those Muslims who are already advocating for reform in their communities, not undermining their efforts by lumping together all Muslims with a relative handful of extremists.

Despite what Donald Trump may wish, facts matter. Or they should, anyway. And we -- and the people we elect -- should get the facts straight about Sharia and Islam. It's in all our interests.