It looks like Homeland Security Secretary Kirstjen Nielsen isn't the only member of the Trump administration on the way out.

The president is also looking for candidates who could replace White House Chief of Staff John Kelly, ABC News reported Tuesday. Right now, the leading contender is reportedly Nick Ayers, Vice President Mike Pence's 36-year-old chief of staff. President Trump has met with Ayers about potentially taking over for Kelly, and they had an "extended conversation" on Election Night, ABC News reports. Some sources said that this is essentially a "done deal," though others said it's not final yet.

It sounds like part of the reason Trump is interested in Ayers is that he sees him as someone who's politically savvy, which he doesn't think is true of John Kelly, per ABC News. Kelly has been rumored to be on the outs with Trump for months on end, but some believe the end is finally nigh now that the midterm elections have passed.

Trump is also reportedly getting ready to fire Nielsen, who has received support from Kelly even as some in the administration criticize her approach. Kelly, who last week was the one to phone Jeff Sessions and tell him he was being forced to resign as attorney general, has reportedly threatened to resign should Nielsen be fired. Now, it sounds like that won't be a problem for Trump, who is ready to get rid of both of them, despite the fact that he had previously asked Kelly to stay on until 2020, reports CNN. Brendan Morrow

A Republican running for Congress in Arizona announced on Monday he is suspending his campaign following a heroin overdose last week.

Chris Taylor is an Army veteran who served two tours in Afghanistan and a member of the City Council in Safford. He has a history of opioid addiction dating back to his high school years. "I'm not going to hide from this," Taylor told The Arizona Republic. "I'm not ashamed of what happened. I wish to sincerely apologize to the amazing people who have supported me."

Taylor told NBC News he is seeking treatment for substance abuse, having relapsed "after having so many solid years in sobriety. I have to figure out where I went wrong. Thankfully I have every resource available to me through the Veterans Affairs Administration and I have the strongest support system one could dream of. The only thing I can do is face this head on in complete humility and put one foot in front of the other so that I can get the help needed to be the father and husband that my family deserves."

Taylor was running in Arizona's 1st Congressional District, hoping to unseat Rep. Tom O'Halleran (D). In his campaign ads, Taylor promised to support President Trump, cut taxes, and defend the Second Amendment. Catherine Garcia

The White House sent a letter to congressional leaders on Monday night, asking for $1.8 billion to spend on its response to the global coronavirus outbreak.

The White House is requesting $1.25 billion in new funding for the Department of Health and Human Services and access to $535 million that had been set aside to fight Ebola, The Washington Post reports. In the letter, White House Office of Management and Budget acting Director Russell Vought wrote: "To this point, no agency has been inhibited in response efforts due to resources or authorities. However, much is still unknown about this virus and the disease it causes. The administration believes additional federal resources are necessary to take steps to prepare for a potential worsening of the situation in the United States."

In response, House Appropriations Chairwoman Nita Lowey (D-N.Y.) said the request was "woefully insufficient." The White House had previously said it did not think it needed any additional funding to fight the COVID-19 coronavirus. There are now more than 50 cases in the United States, and organizations representing state and local public health officials have asked for money to buy protective equipment, expand outreach to the public, and fund mobile home-testing teams, the Post reports. Catherine Garcia

After holding an abdominal plank for 8 hours and 1 minute, George Hood surpassed the world record and could have stopped, but he had a reason to keep going.

Hood, a 62-year-old former Marine and retired Drug Enforcement Administration agent from Naperville, Illinois, broke the record on Feb. 15 at 515 Fitness, a gym that aims to end the stigma of mental illness. Hood wanted to raise awareness of how exercise can help improve mental health and dedicate his feat to the gym, so he held his plank for 8 hours, 15 minutes, and 15 seconds in order to get "515" in the time.

A father of three, Hood first set the male world record for longest plank in 2011, CNN reports. For 18 months, he trained on average seven hours a day — he would practice his plank pose for four to five hours, and then do 700 pushups, 2,000 sit ups, 500 squats, and 300 arm curls. To get through the pain, he listened to his favorite music at maximum volume.

"When it gets tough, you know what I do?" he told CNN. "I turn that music up so loud, you'd think you're at a rock concert. I always had a fantasy of being a rock star back in the '80s. And at least for those 8 hours, 15 minutes, and 15 seconds, I was a rock star." Catherine Garcia

The National Institute of Allergy and Infectious Diseases is expected to soon launch a clinical trial of an experimental coronavirus vaccine.

The vaccine was developed by the drugmaker Moderna, and researchers hope to begin testing it on humans in late April. The first trial will involve 20 to 25 healthy volunteers, with results expected by July or August. If that round is successful, a second trial will include hundreds or thousands of subjects. The vaccine was created after the coronavirus' genetic sequence was determined in January.

"Going into a Phase One trial within three months of getting the sequence is unquestionably the world indoor record," NIAID Director Anthony Fauci told The Wall Street Journal on Monday. "Nothing has ever gone that fast."

Gene-based technology has yet to result in an approved vaccine for humans, the Journal reports. If this vaccine does work, it will still have to go through regulatory measures, and likely won't be widely available until 2021. Fauci said the virus might not spread as quickly in the summer due to the heat, but could roar back in the winter. More than 2,600 people have died in this coronavirus outbreak, and there are more than 79,000 confirmed cases worldwide, with most in China. Catherine Garcia

If you're one of President Trump's former national security advisers, you're doing a lot of waiting these days — either for your book to be published or for your prison sentence to be decided.

Lt. Gen. H.R. McMaster was Trump's second national security adviser, serving from March 2017 to April 2018. He came on board after Trump's first national security adviser, Michael Flynn, resigned; Flynn later pleaded guilty to lying to the FBI about his interactions with the former Russian ambassador to the United States.

McMaster has written a book, Battlegrounds: The Fight to Defend the Free World, set to be published on April 28. HarperCollins says it is a "groundbreaking reassessment of America's place in the world, drawing from McMaster's long engagement with these issues, including 34 years of service in the U.S. Army with multiple tours of duty in battlegrounds overseas." It will also include information on McMaster's "13 months as national security adviser in the Trump White House."

Unlike other former members of the administration, McMaster, now a fellow at the Hoover Institution at Stanford University, has not given many interviews about his experience with Trump. One of his aides was quoted in the book A Very Stable Genius as saying, "The president doesn't fire people. He just tortures them until they're willing to quit."

Trump's third national security adviser, John Bolton, finished writing his book, The Room Where It Happened, last year. It is supposed to come out in March, but the White House is reportedly trying to block its release. Bolton, who served from April 2018 to September 2019, is said to have included damaging information in the book, including that Trump attempted to get him to engage in a quid pro quo with Ukraine. Catherine Garcia

Former Vice President Joe Biden's campaign team is going after Sen. Bernie Sanders (I-Vt.) for reportedly once going after Biden's old boss.

The Biden campaign unveiled a new digital ad Monday that's tied to a story published The Atlantic last week that reported Sanders seriously considered launching a primary challenge against former President Barack Obama in 2012. When word got around to the Oval Office, it reportedly sent Obama's re-election campaign team into a panic.

Sanders' camp quickly denied the senator ever contemplated trying to unseat Obama, but regardless, the Biden team is unleashing the story against the new national frontrunner in a state where the former vice president is still considered the favorite. In the ad, they accuse Sanders of trying to undermine Obama's re-election, and argue he "can't be trusted" to build upon the president's legacy. Watch the full ad below and read more at Politico. Tim O'Donnell