Newsletter: Opinion: Donald Trump. Again.

Good morning. I'm Paul Thornton, The Times' letters editor, and it is Saturday, Dec. 12, 2015. Happy 15th birthday, Bush vs. Gore. Speaking of presidential campaigns that will live in infamy ...

Don't feed a troll, the saying goes, and Donald Trump's presidential campaign has been sustained by the refusal of people to take this advice. We've seen it before: He says something offensive and outlandish, takes criticism from even his fellow Republicans and emerges only further ahead in the GOP presidential race.

But he might have outdone himself by calling for all Muslims to be banned from entering the United States. The Times' editorial board, admittedly reluctant to admonish Trump for fear of giving him more attention, says he has managed to "make his demagoguery even uglier." It writes:

Now he's outdone himself. On Monday, Trump demanded a "total and complete shutdown" of immigration by Muslims, an idea so far out of the mainstream that Jeb Bush called him "unhinged" and Sen. Lindsey Graham (R-S.C.) called him a "race-baiting, xenophobic, religious bigot."

Unsatisfied with linking a billion and a half Muslims to terrorism, Trump defended his comments Tuesday by invoking President Franklin Roosevelt's decision to classify Germans, Japanese and Italians as "enemy aliens" during World War II. No, Trump insisted, he wasn't calling for internment camps for Muslims today. But asked whether he would have supported interning people of Japanese ancestry during the war, Trump told Time magazine: "I would have had to be there at the time to tell you, to give you a proper answer. I certainly hate the concept of it. But I would have had to be there."

Surely Trump knows (or maybe he doesn't) that the Japanese internment is one of the great embarrassments of American history. In 1988, President Reagan offered a long-overdue formal apology and compensation to 100,000 people of Japanese ancestry (many of them U.S. citizens) unfairly incarcerated during the war.

No-nothingism has its charms. Populism is popular. But Donald Trump's demagoguery long ago ceased to be amusing.

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Is this Trump's Last Stand? Republican insiders hope so. In their roundup of the latest Trump chatter, Jon Healey and Julia Kingsley note that Republicans are distancing themselves from their party's front-runner in the hope that his toxicity doesn't infect them (even though there's evidence to suggest that among GOP voters, Trump's doing just fine). Editorial writer Michael McGough says journalists should resist the urge to ignore Trump's comments, advice that Times readers are taking.

Stop calling Antonin Scalia a racist for his comment about black students attending "less advanced" schools. In fact, McGough writes, the Supreme Court justice was merely touching on a theory central to the idea that minority students deserve some racial preference (affirmative action, in other words) to attend and benefit by graduating from prestigious schools to which some might not have otherwise been admitted. L.A. Times

California, the capital of Christmas: No, really — our modern idea of the quintessential winter celebration was shaped and propagated right here. Joe Mathews writes: "Bethlehem, Shmethlehem. It is the Golden State that popularized the modern Christmas via our entertainment industries, that designs it through our toymakers, digitizes it through Silicon Valley, distributes it through our ports, and provides unparalleled settings to celebrate it, with mountain skiing and Pacific surfing both doable in a single Christmas Day." Zócalo Public Square

Land on the no-fly list, and still be able to buy a gun? That's the way it should be, says The Times' editorial board. Like it or not (and the board doesn't), buying a firearm has been recognized by the U.S. Supreme Court as a personal right, and we should not be in the business of curtailing constitutionally guaranteed liberties for those who haven't been charged with or convicted of a crime. In a letter to the editor, Sen. Dianne Feinstein says she finds it "shocking that The Times believes a known or suspected terrorist should be able to legally purchase firearms and explosives."

Will your driverless car kill you so others can live? Eric Schwitzgebel says state regulators must seriously consider hypotheticals like this one: "It's 2025. You and your daughter are riding in a driverless car along Pacific Coast Highway. The autonomous vehicle rounds a corner and detects a crosswalk full of children. It brakes, but your lane is unexpectedly full of sand from a recent rock slide. It can't get traction. Your car does some calculations: If it continues braking, there's a 90% chance that it will kill at least three children. Should it save them by steering you and your daughter off the cliff?" L.A. Times

Ignorance among the young and healthy could doom L.A.'s mobility plan. Ali Swenson, who describes herself as "young, healthy and able-bodied," says the success of City Hall's effort to coax people out of their cars and onto bikes, trains or buses might be impossible if people like her — the most physically capable of pedaling across Los Angeles — don't know much about cycling in this city and choose to stay in their cars. Swenson gets herself up to speed by signing up with L.A. Bike Trains and goes on to find herself cycling safely to work from the Westside to downtown. L.A. Times

Have feedback? Send it to paul.thornton@latimes.com.