Jay Parini, who teaches at Middlebury College, is the author of " The Way of Jesus: Living a Spiritual and Ethical Life ." The views expressed in this commentary are his own. View more opinion articles on CNN.

The mass shooting at a synagogue in Pittsburgh on Saturday is horrifying. Men, women and children at prayer should feel safe. Racist and anti-Semitic hatred should have no place anywhere in this country.

As we mourn the 11 dead and the injured others, including the law-enforcement officers who ran selflessly toward the gunfire, we are saddened but not surprised. Racism gathers into its dark embrace haters of every kind. Their victims can be of any minority group -- Jew, Muslim, Latino, black, gay. And for a country awash in guns, hate erupting into murderous violence is a chronic condition.

Bigoted hatred is self-loathing fueled by fear. Bigots do not feel good enough about themselves to accept those they see as different. They cannot tolerate unfamiliar ideas or traditions. Diversity frightens them. White racists want to hear only the language they know: English. They wrap themselves in the American flag, calling themselves patriots while knowing nothing about the long tradition it represents, flying over a nation that welcomes people of all races, creeds and religions to our shores.

I often think of George Washington's beautiful letter to the Jews of Rhode Island. He wrote the letter on August 18, 1790, after a visit to the Newport congregation, which had fled persecution in Europe. He assured them they would find "toleration" on these shores, liberty for people of all faiths. Religious freedom here was an absolute, he wrote, and all creeds were welcome. He quoted from the Hebrew scriptures, saying that "everyone shall sit in safety under his own vine and fig tree, and there shall be none to make him afraid."

This is so heartbreaking: "And there shall be none to make him afraid."

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We have only the barest outline of the accused shooter, Robert Bowers. He apparently yelled "all Jews must die" as he entered the Tree of Life synagogue and opened fire. He was armed with the usual AR-15 -- the weapon of choice for most mass shooters in this country. (It is a travesty that these weapons of mass destruction are available to almost anyone, and will be as long as our Congress and courts are enslaved to the gun lobby.)

Bowers apparently liked to go on social media, so we found out quite a lot about him quickly. Bowers like to post on Gab =- an alternative to Twitter, that advocates for free speech and puts nearly no restrictions on content -- with crazy assertions like Jews are "the children of Satan."

This madness is not Christian, and that quotation, supposedly from the New Testament, is twisted. Jesus said no such thing, nor did he himself ever deny being a Jew. His followers called him rabbi, meaning teacher. Indeed, the early Christians were largely considered by the Romans as a kind of Jewish sect, and this wasn't terribly far off the mark, as so many of the essentials of Christianity owe their shape and tenor to the Hebrew scriptures, which the writers of New Testament took great pains to quote lavishly.

Not long before Saturday's mass murder, Bowers wrote on Gab: "HIAS likes to bring invaders in that kill our people. I can't sit by and watch my people get slaughtered. Screw your optics, I'm going in." HIAS stands for the Hebrew Immigrant Aid Society, and it's a group with a long and noble history of aiding refugees of all kinds, not only Jews. They have been working for over 130 years, helping those displaced because of their race, ethnicity, religion or sexual identity. Their motto is: "Welcome the stranger. Protect the refugee."

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I wish that motto were engraved on Americans coins!

Americans: wake up, please! Remember why we exist at all: we were founded by immigrants fleeing persecution abroad, our pilgrim fathers and mothers. We're a nation of refugees, by refugees, and for refugees. Our sad history, of course, includes the tragedy of slavery and Jim Crow, and we need to work especially hard in the decades to come to overcome the legacy of this hatred of African Americans as well as our appalling attitudes toward Mexicans and other immigrants.

Of course, this won't be easy, not in the wake of President Donald Trump's endless barrage of hate speech.

This is a presidency founded in the racism of his birther claims against President Barack Obama and his initial excoriation of Mexicans as rapists and drug dealers (followed by an unreal litany of vile comments about Mexicans during his presidency). It's not going too far to suggest that his recent rhetoric has fueled and empowered racists of every stripe by creating a fantasy of "us" versus "them."

We are not two nations. We are one.

The President acknowledged as much in a statement Saturday: "We must all rise above the hate, move past our divisions and embrace our common destiny as Americans, and it doesn't mean we can't fight hard and be strong and say what's on our mind, but we also have to remember those elements, we have to remember the elements of love and dignity and respect and so many others," Trump said.

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These are the right words, of course. Unfortunately this righteous sentiment wars with so many other statements of our hater-in-chief. The President is not -- as Bower noted -- an anti-Semite. (Indeed, in a statement Saturday, the President said "with one unified voice we condemn the historic evil of anti-Semitism and every other form of evil and unfortunately, evil comes in many forms.")

"Trump is surrounded by k****," Bowers wrote on social media, and so "things will stay the course." He didn't vote for Trump, he wrote -- and considers him a "globalist, not a nationalist" -- even though the President went out of his way to dog-whistle to a cheering crowd last week in Houston: "I am a nationalist." Only someone not listening wouldn't have caught the President's meaning there, that he was signaling to those in the audience who embraced a racist ideology.

It is beyond depressing that the party that supports him would tolerate such a person as their head -- and just because he gave them their tax cuts and right-wing judges. Shame on them, and shame on any American who doesn't speak up to renounce hatred.

Anti-Semitism -- and all forms of racism -- have no place in America. And it will be a happy day on these shores when people of every color and religion stand together as a nation.

We can have disagreements on policy, of course. Strong ones. But these should be family arguments, conducted under the assumption that we are united by a common passion for justice and equality, an awareness that liberty only has meaning when it applies to everyone.