As I write this, the uproar regarding President Donald Trump’s executive order to restrict immigrants from seven predominantly Muslim countries is in full swing.

Certainly, there are people on the left who will oppose anything the president puts in place. I am convinced that if President Trump got up tomorrow morning and walked on water, his detractors would say, “You see, he can’t even swim!”

But this uproar does have foundation. After all, we are a nation of immigrants. Unless you are a Native American, your ancestors came here from somewhere. Many reading this are descendants of those escaping religious persecution in Europe.

So, I completely understand the sentiment that to reject immigrants is in some ways un-American. Likewise, to base that rejection on religion is particularly ironic given the reason so many of our forefathers decided to make the trip across the Atlantic.

However, the reality is that this issue is much more complicated than that. The problem at its core is not Islam; the problem is what Islam can bring with it.

And what do Muslims bring with them? Some proponents of the recent ban point to Sharia law as the problem associated with immigration from Islamic countries. It is not.

“Sharia” is what believing Muslims see as an idealized world of divine justice, a way of living that reflects God’s will. It is a kind of divine blueprint for human life.

To a Muslim, Sharia, which can be found in the Quran and in the actions of the prophet Muhammad, governs their day-to-day life.

By definition, all Muslims believe in Sharia. It is not the case that some Muslims believe in Sharia and some don’t, just as it is not the case that some Christians believe in Christ’s sacrifice on the cross and some don’t.

What is very important to understand is a deeper fact – that there is extreme variation in how Sharia is interpreted and implemented among and within Muslim societies.

And that is the real issue. In fact, the Arabic word, “fiqh,” refers to the interpretation and application of Sharia as practiced by people.

In other words, all Muslims will seek to follow Sharia. How that dedication to Sharia will affect their lives and the lives of those around them is a matter of fiqh. Some may live peacefully; others not so much.

There are extreme schools of thought on “fiqh.” And those extremists often use violence, couched in “jihad” (literally, “a struggle against enemies of Islam”), to influence others in their radical thinking.

These Sharia fundamentalists legitimize their violent actions by referring to Sharia, although a majority of Muslims “modernists” reject that idea.

The over-riding problem we face here is that we don’t know who the violent extremists are and aren’t.

Some Christians refers to Sharia itself as antithetical to the U.S. Constitution. They claim that adherence to Sharia fundamentally conflicts with our values of liberty and equality.

Some of that may be true. There have been problems of Muslims trying to impose Sharia on non-Muslims, which have often led to violence in African and European countries. The areas where Sharia may be incompatible with U.S. laws and values are in governmental structure, human rights, women’s rights, and freedom of expression.

Franklin Graham, renowned evangelist Billy Graham, said of refugees, “We need to be sure their philosophies related to freedom and liberty are in line with ours.”

It seems to me that the president has decided to err on the side of caution until such time that vetting can ensure, to the extent it ever can, that we know who the violent extremists are and aren’t.

I do not have a foolproof solution to this problem. But such a solution will never be found if we cannot identify the basic underlying issues that drive Islamic extremists.

Perhaps Nmachi Abengowe has something for us to consider. The 62 year-old native of Nigeria cited Muslim-on-Christian violence in Africa in defending Mr. Trump’s preference for Christian refugees.

“They believe in jihad,” he said of Muslims. “They don’t have peace. Peace comes from Jesus Christ.”