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

At least one person was killed and five more injured in Portland, Oregon, on Monday afternoon as an unidentified driver went on a hit-and-run spree, steering his silver Honda Element on sidewalks and over laws as he apparently targeted pedestrians along a 15-block stretch in the Southeast quadrant of the city. After the man crashed into an El Camino, neighbors and bystanders prevented him from escaping by foot until police arrived and took him into custody.

Videos of the arrest show the man, who appears to be white and middle-aged, in a standoff with bystanders before police arrived and struggled to put him in cuffs. Several witnesses told The Oregonian the car had Washington plates. Police have not released the name of the driver or any of his victims.

Larry Wolfe told The Oregonian he had an appointment to meet the person killed, a woman in her 70s, and he saw the car hit the woman, turn around and hit her again, then do a U-turn and drag her down the street. Another witness, Arun Gupta, gave a similar account to OPB. "She was struck once, knocked up on the sidewalk ... and then the car did a U-turn, came up on the sidewalk, struck her and dragged her down to Stark and 19th," he said.

Other witnesses described a chaotic scene where the driver, speeding and running red lights, hit cyclists, struck several pedestrians, and pinned two people between and SUV and a retaining wall. Read more witness accounts at The Oregonian. Peter Weber

President Biden is expected to announce several executive actions on Wednesday meant to fight climate change, including one asking government agencies to determine the extent of a drilling ban on federal land, two people with knowledge of the matter told The New York Times on Monday.

Additionally, Biden intends to direct the government to conserve 30 percent of all federal land and water by 2030, make climate change a national security priority, and form a task force to create an action plan on ways to reduce greenhouse gas emissions, the Times reports. He will also create multiple commissions to focus on environmental justice and green jobs, specifically helping minority communities and people who live in coal country.

Environmentalists say to really curb harmful emissions, Biden will have to enact legislation; otherwise, he will need to rely heavily on the regulatory process. "The climate reality of today is higher temperatures, stronger storms, more destructive wildfires, sea-level rise, acidifying oceans, and extended drought," Sherri Goodman, senior fellow at the Wilson Center's Environmental Change and Security Program, told the Times. "We need a climate security plan for America that climate-proofs American infrastructure and puts climate and clean energy innovation front and center." Catherine Garcia

In an interview with MSNBC's Rachel Maddow on Monday afternoon, Senate Majority Leader Chuck Schumer (D-N.Y.) said his caucus won't allow Minority Leader Mitch McConnell (R-Ky.) to dictate the agenda in the Democratic-led 50-50 Senate or demand an end to the legislative filibuster as a precondition for a power-sharing pact. "We've told McConnell no on the organizing resolution, and that's that. So there's no negotiations on that," Schumer said, suggesting he had a secret plan. "There are ways to deal with him."

Maddow included an update when she broadcast the interview Monday night. "While we were airing that right now, and you were watching it, Republican Minority Leader Mitch McConnell just put out a statement that he is folding on this" and willl "agree to go forward with what Sen. Schumer told him he must," she said. "Sen. Mitch McConnell has caved and Sen. Schumer has won that fight. That was quick. Let's see what else we can do."

McConnell said he would allow the Senate to move forward because two Democrats had reiterated their opposition to ending the filibuster, effectively taking that option off the table. Maddow asked Schumer about that, too, and he didn't answer directly.

"The caucus is united with the belief that I have: We must get big, strong, bold things done," Schumer said. The Democratic caucus is also "totally united" that "we will not let Mitch McConnell dictate to us what we will do and not do," and "we have tools that we can use," notably the budget reconciliation process," he added. "We will come together as a caucus and figure it out."

Schumer also suggested he is not interested in playing cat-and-mouse with McConnell's Republicans again. Watch below. Peter Weber

Senate Minority Leader Mitch McConnell (R-Ky.) on Monday night said that since Sen. Kyrsten Sinema (D-Ariz.) and Sen. Joe Manchin (D-W.Va.) promised they have no intention to vote to abolish the 60-vote legislative filibuster, he will support a power-sharing agreement with Democrats.

With Democrats in control of the House and Senate, some lawmakers have called for the elimination of the filibuster, and McConnell spent days stalling and trying to get Senate Majority Leader Chuck Schumer (D-N.Y.) to guarantee he would preserve it. The Senate is split 50-50; the last time this happened was in 2001, and the party with the vice presidency controlled the floor agenda.

In a statement, McConnell said he is ready to move forward on a deal "modeled" on the 2001 "precedent" after Sinema and Manchin said they "agree with President Biden's and my view that no Senate majority should destroy the right of future minorities of both parties to help shape legislation."

Justin Goodman, a spokesman for Schumer, said Democrats are "glad Sen. McConnell threw in the towel and gave up on his ridiculous demand. We look forward to organizing the Senate under Democratic control and start getting big, bold things done for the American people." Catherine Garcia

An Ohio state senator who questioned the hygiene of Black people has been tasked with leading a state health panel, over the objection of several lawmakers.

During a hearing last June, state Sen. Steve Huffman (R), a physician, said he understood that "African Americans have a higher incidence of chronic conditions and that makes them more susceptible to death from COVID. But why does it not make them more susceptible just to get COVID?" He questioned whether "the colored population" washed their hands, wore masks, or practiced social distancing "as well as other groups. ... Could that be the explanation for why the higher incidence?"

After an immediate backlash, Huffman apologized for his remarks.

This month, Huffman was appointed by Senate President Matt Huffman (R), his cousin, to lead the Ohio Senate Health Committee, which reviews legislation about health care and human services. This angered multiple lawmakers, including state Rep. Catherine Ingram (D), who said Huffman's "racist and problematic remarks" are proof he is not fit to head the committee.

In a statement to CNN, Huffman said he is "one of the few doctors in the legislature," and is "proud" to have been named chair of the Ohio Senate Health Committee. The question he asked in June was "awkwardly worded" and "unfortunately hurt many people," Huffman said, adding that he has since attended "classes on diversity and inclusion." Catherine Garcia

The Minnesota Department of Health announced on Monday it has recorded the first known case in the U.S. of the highly transmissible COVID-19 variant that has been spreading through Brazil.

Known as the P.1 variant, it was detected amid a surge of cases in Manaus, Brazil. Minnesota health officials said the patient is a resident of the Twin Cities area who recently traveled to Brazil, and the strain was found via genomic sequencing of random blood samples. The person was tested on Jan. 9, and is now in isolation. Ruth Lynfield, Minnesota's state epidemiologist, said this is a reminder why "it is so important to limit travel during a pandemic as much as possible."

Scientists are closely studying three COVID-19 variants: P. 1, as well as B.1.1.7, first detected in the United Kingdom, and B1.351, first identified in South Africa. Virologists said the variants are independent of one another but there is some overlap in the mutations. The U.K. variant is spreading now in the U.S., but the South Africa variant has not yet been detected. Virologists are especially concerned that the Brazil and South Africa variants contain mutations that may evade the protections of some antibodies.

William Hanage, an epidemiologist at the Harvard T. H. Chan School of Public Health, told The Washington Post on Monday the Brazil variant is "probably the one causing the most concern among people watching this. It is fair to say that P.1 is the object of very, very serious attention and concern among epidemiologists. We don't know why it has been so successful in Manaus." Catherine Garcia