A significant part of the federal government is shut down indefinitely because President Trump is insisting on $5 billion for a border wall (or steel fence) and Democrats are saying no. But Trump's "wall" fixation actually began as little more than "a memory trick for an undisciplined candidate," Julie Hirschfeld Davis and Peter Baker report at The New York Times.

As Mr. Trump began exploring a presidential run in 2014, his political advisers landed on the idea of a border wall as a mnemonic device of sorts, a way to make sure their candidate — who hated reading from a script but loved boasting about himself and his talents as a builder — would remember to talk about getting tough on immigration. [The New York Times]

Trump embraced the idea once he saw the enthusiastic response his promise of a Mexico-funded border wall received among conservative audiences. "He's very obsessed about carrying out his campaign promises — I think to a degree that's unhealthy — but that's important to him, and that's not a bad thing," Trump friend Christopher Ruddy, CEO of Newsmax, tells the Times. White House counselor Kellyanne Conway says Trump is "focused on the wall" because "he thinks you need a very robust physical barrier at the border that you can't climb over, slide under, drive through or walk around." Her husband, George Conway, had a different interpretation:

Many of Trump's fellow immigration hardliners view his wall as a counterproductive, minor-to-insignificant part of broader restrictions on legal and illegal immigration. You can read more about the genesis of Trump's wall, and its critics on both sides of the immigration debate, at The New York Times. Peter Weber

Mort Drucker, the beloved artist known for his work at MAD magazine, has died at 91.

Drucker died Wednesday at his home in New York, his friend John Reiner confirmed to The New York Times. Reiner told CNN's Jake Tapper his death was not thought to be related to COVID-19.

After joining MAD in 1956, Drucker's hilarious caricatures satirizing pop culture soon became iconic, and he illustrated more than half of the magazine's movie parodies from the 1960s through 2008, per the Times. In a 2000 interview with the Times, he noted, "I think I've drawn almost everyone in Hollywood."

Among Drucker's other notable work includes the poster for George Lucas' American Graffiti; according to The Hollywood Reporter, Lucas personally drove to Drucker's home on Long Island to convince him to draw it.

"The World has lost a not just an extraordinary talent but a shining example of kindness, humility and humor," the National Cartoonists Society said in a statement.

MAD fans on Thursday quickly began sharing their favorite cartoons from Drucker's legendary career, including his parodies of Jaws and Star Wars. "Many of his illustrations are as vivid in my mind as the movies and TV shows that inspired them," The New York Times' Dave Itzkoff wrote.

Reiner told CNN's Jake Tapper that Drucker's final words to him were, "I'm the luckiest man — I've had a wonderful life." Brendan Morrow

First lady Melania Trump is officially donning a face mask during the COVID-19 pandemic, although the jury's still out on whether her husband will follow suit.

In a social media post Thursday, the first lady shared a photo of herself wearing what appears to be a surgical mask, touting the Centers for Disease Control and Prevention's recommendation "to wear cloth face coverings."

"Remember, this does NOT replace the importance of social distancing," she wrote. "It is recommended to keep us all safe."

Melania's masking comes one week after President Trump announced he would not be wearing a mask, despite the CDC-issued guidelines urging people to do so. At the time, Trump implied that it would be odd to be "sitting in the Oval Office, behind that beautiful Resolute Desk" while wearing a mask, so it's unclear how he's taking this news.

The photo of the first lady appears to show her wearing a surgical mask rather than the CDC-recommended "cloth face covering," the former of which is recommended only for use by health care professionals and medical first responders amid critical supply shortages.