The best line of Wednesday’s Republican presidential debate came from Ronald Reagan.

I don’t mean any of the many times that the Republican candidates invoked the 40th president of the United States as they stood in front of the airplane that once served him as Air Force One, but rather an ad that ran during one of the commercial breaks, sponsored by the National Immigration Forum Action Fund.

The minute-long clip features part of President Reagan’s farewell speech to the nation in 1989. Speaking straight into the camera, Reagan describes what he pictures in his head when he refers to America as a “shining city on a hill,” one of his favorite rhetorical devices.

“In my mind it was a tall, proud city built on rocks stronger than oceans, wind-swept, God-blessed and teeming with people of all kinds living in harmony and peace,” said Reagan. “If there had to be city walls, the walls had doors and the doors were open to anyone with the will and the heart to get here. That’s how I saw it, and see it still.”

Reagan’s words of inclusion would have been powerful on their own, but the ad heightened their impact by interspersing them with some of the worst that 2016 Republican presidential candidates have said so far about immigrants – starting, of course, with front-runner Donald Trump.

I’ve always loved the “city on a hill” metaphor for the United States. It’s a biblical phrase from Jesus’ Sermon on the Mount, first applied to this continent by John Winthrop in 1630. He roused his fellow future Massachusetts Bay colonists to build such a settlement “that men shall say of succeeding plantations, ‘may the Lord make it like that of New England.’ ”

“For this end, we must be knit together, in this work, as one man,” said Winthrop to that boatload of immigrants. “We must entertain each other in brotherly affection. We must be willing to abridge ourselves of our superfluities, for the supply of others’ necessities. We must delight in each other; make others’ conditions our own; rejoice together, mourn together, labor and suffer together, always having before our eyes our commission and community in the work, as members of the same body.”

Declaring America to be a shining city and a light for the world isn’t meant as an arrogant statement, at least the way I hear it.

It’s a hopeful and purposeful declaration that we have the unparalleled opportunity here, in the world’s first modern democracy and the world’s last remaining great superpower, to build a society and a nation that will be a source of inspiration and an example of the best that people can achieve.

We may not yet have become the model of inclusion and community that Winthrop’s and Reagan’s words invoke, but generations of Americans have worked to bring us closer to that ideal.

Few things could be further from this vision than the anti-immigrant attacks from the current crop of Republican candidates. Just this week, a Trump supporter at a rally declared that “We have a problem in this country. It’s called Muslims,” and asked the candidate, “When can we get rid of ’em?”

“We are going to be looking at a lot of different things. And you know, a lot of people are saying that,” was Trump’s reply.

Maine Gov. Paul LePage, never one to be left behind when it comes to ignorant and divisive statements, also popped up on the presidential campaign trail to take some shots at immigrants. At a Chris Christie event in New Hampshire on Sunday, he attacked Portland for being too welcoming to folks from away.

As is often the case, LePage’s claim about Portland being a “sanctuary city” turned out to be untrue, but the real issue isn’t that he was wrong. It’s that he was wrongheaded.

Immigration and immigrants aren’t something to fear, but to embrace. Not only is it the right thing to do, on a basic human level, to show an open door to those with the will and heart to get here, but it’s essential for Maine’s future.

We’re the oldest state in the country, with a shrinking population and labor force. We need the individual and collective vitality of new Mainers. There are good reasons why inclusive Portland is our state’s economic powerhouse.

Trump, LePage and Republicans everywhere should start treating immigrants as people, not problems, and they should stop threatening to build higher walls and instead get to work building that shining city, a beacon to the world.

Mike Tipping is a political junkie who blogs at MainePolitics.net and works for the Maine People’s Resource Center. He can be contacted at:

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Twitter: @miketipping