There are times when the sort of coolly measured tone of a standard opinion piece for Christian Today is just not appropriate. You just have to say, "Look, you're wrong, and someone needs to break your computer so you can't email this stuff to anyone any more."

A letter to the Alabama Baptist news service by the pastor of Arbor Springs Baptist Church in Northport, Alabama, is the perfect example. Rev Ted Sessoms decided to pronounce on the Syrian crisis, which has seen an estimated 9 million leave their homes.

To remind readers: we have seen harrowing scenes of children starving, families bombed out of their homes and forced into freezing and insecure refugee camps, the horrifically injured and the inconsolably bereaved. Against the fierce opposition of many in his country who are unconvinced of the effectiveness of security checks, President Obama proposed to accept 10,000 of them into the US. Evangelical leaders, to their credit – including many from Sessoms' own Southern Baptist Convention – said that this was a good thing, as long as they could be reasonably sure they weren't importing terrorists.

For Sessoms, though, this doesn't go nearly far enough. He expresses his "disappointment" with his denomination's leaders, following this with an unwittingly self-revelatory sentence: "I am against allowing the refugees the rights to America's soil and my neighborhood. These are the same people that hate America, hate Christians and have vowed to take over the world by destroying our way of life." He suggests SBC leaders study Old Testament examples of herem, the total destruction of whole communities including women, children and animals. "It is not a matter of loving your neighbor," he says. "My neighbors are the people that value the same standards of life and way of life that I value."

Really? Even leaving aside the truly sinister reference to "America's soil", I'd have thought Jesus' parable of the Good Samaritan, where in answer to the question "Who is my neighbour?" he mentions a traditional enemy of Israel, was enough to answer that one.

Sessoms continues: "We owe it to our children and grandchildren to make good decisions for their future in America. And opening up our country to tens of thousands of refugees with their unknown background but known hatred for Christianity and America will destroy any future our children may have.

"These are the same people that are willing to give their lives to carry out their commitment to Allah. They don't have to be considered terrorists to hate Christians. Their religious conviction cause them that hatred."

Apart from the fact that it's 10,000, not tens of thousands, and that the idea of this number posing a threat to a nation of 320 million is utterly absurd, the pastor's rhetoric is, once again, revelatory. It doesn't matter that these refugees might be traumatised by the loss of everything they possessed. They might be injured and in pain, bereaved, frightened of starting life as strangers in a strange land. None of this matters: they are, or so he assumes, Muslims (the notion there might be Christians among them has not occurred to him) and that's enough for Sessoms to assume they are his mortal enemy. As such, the right to freedom of religion – surely an American value if anything is – can be abrograted, because Islam is just different. 

In the normal way of things Sessoms' arguments wouldn't be worth the trouble of a response, several have – and have roundly condemned him. 

But put his rant together with the improbable rise of Donald Trump, and there's a problem. Trump could very plausibly win the Iowa primary. A Bloomberg poll of polls shows him ahead nationally. And Trump's rhetoric is from the same playbook as Sessoms'. It demonizes, divides, misrepresents and excludes. Trump's public attitude to Muslims may, in truth, be due to a political calculation rather than a heart-felt conviction (of which he appears to have very few) but that's not the point: it's his anti-Muslim rhetoric and his hardline stance on immigration (seriously, a wall along the entire southern border) that are helping to drive his popularity.

So, ignorant and offensive as his letter is, does Sessoms actually speak for a sizeable minority of Americans? And if so, has he, again unwittingly, performed a public service in revealing the dark heart of the Trump phenomenon?

Evangelicals are voting for Trump in large numbers, in spite of the trenchant criticisms of him expressed by the highly respected conservative figure Russell Moore, among others. Maybe this horrifying vision of the company they're keeping will appeal to their consciences where his reasoned arguments don't.

Follow Mark Woods on Twitter: @RevMarkWoods