National Security Adviser H.R. McMaster said Saturday the risk of war between the United States and North Korea is "increasing every day," arguing Pyongyang is "the greatest immediate threat to the United States" and "we are in a race to be able to solve this problem." He did concede there are "ways to address this problem short of armed conflict," but said there is "not much time left" for those options because of North Korea's technological progress.

In an interview with Chris Wallace on Fox News Sunday, McMaster similarly argued preventive war — for the U.S. to attack North Korea to prevent the materialization of a possible future threat — may be the only option to stop "this murderous, rogue regime" from conquering South Korea and starting an Asian nuclear arms race. He brushed aside Wallace's point that the U.S. learned to coexist with a nuclear Soviet Union for decades during the Cold War, suggesting that to repeat that strategy would be too risky for U.S. security.

Watch McMaster's full Fox interview below, and read The Week's Harry J. Kazianis on the deadly consequences of McMaster's proposal. Bonnie Kristian

On the eve of Lt. Col. Alexander Vindman's public testimony before House impeachment investigators, Sen. Ron Johnson (R-Wis.) sent a letter to House Republicans, questioning Vindman's credibility.

Vindman, the National Security Council's top Ukraine expert and a Purple Heart recipient, is set to testify on Tuesday. He listened to President Trump's July 25 phone call with Ukrainian President Volodymyr Zelensky, and immediately shared his concerns over Trump's request that Zelensky launch an investigation into a political rival, former Vice President Joe Biden, and his son, Hunter.

In his letter, Johnson opines that there are "bureaucrats and staff members within the executive branch" who have "never accepted President Trump as legitimate and resent his unorthodox style and his intrusion onto their 'turf.' They react by leaking to the press and participating in the ongoing effort to sabotage his policies and, if possible, remove him from office. It is entirely possible that Vindman fits this profile."

Johnson tried to defend Trump throughout the letter, saying he could not recall Trump ever talking to him about the Bidens, while also attacking the whistleblower whose complaint about Trump's call launched the House impeachment inquiry. "If the whistleblower's intention was to improve and solidify the relationship between the U.S. and Ukraine, he or she failed miserably." Catherine Garcia

Since being deported from the United States, Maria Butina has received several job offers in Russia, including one with the human rights commission.

Butina, 31, pleaded guilty last year to one count of conspiring to act as a foreign agent for Russia. She infiltrated the National Rifle Association and influenced Republican and conservative activists to promote Russian interests in the 2016 presidential election. She was sentenced to 18 months in prison, but was released last month after serving 15 months. She was deported on Oct. 26.

When she arrived back in Russia, Butina was greeted by cheering supporters. She made her first public appearance since then on Monday, alongside the country's human rights commissioner, Tatyana Moskalkova. Moskalkova invited Butina to "work in our group defending compatriots abroad," explaining: "I'm sure together we'll be able to do a lot of good for people who've ended up in tough situations abroad." Butina did not say if she'll take the job or if she'll accept another offer to work in Russia's lower house of parliament, Reuters reports.

Also on Monday, Butina's former boyfriend, conservative political operative Paul Erickson, pleaded guilty to one count of wire fraud and one count of money laundering. Authorities say the South Dakota businessman promised dozens of clients returns of up to 150 percent, but in reality stole $2.3 million from them. He was accused of using this money on personal expenses for Butina. Catherine Garcia

Two prison guards assigned to watch accused sex trafficker Jeffrey Epstein on the night he took his own life are expected to be charged with falsifying prison records, a person with knowledge of the matter told The Daily Beast on Monday.

Epstein was arrested on July 6 and held in New York City's Metropolitan Correctional Center while awaiting trial on charges of sex trafficking and conspiracy. Epstein was in a special unit, and while he was no longer on suicide watch, guards were supposed to check on him every 30 minutes. On Aug. 10, he was found hanging from a bed sheet in his cell, and the New York City medical examiner confirmed that his death was a suicide.

Federal investigators have been trying to determine how Epstein was able to take his own life, and there have been multiple reports that the unnamed guards fell asleep on the job and altered records to cover their tracks. The charges against the guards could be filed as soon as Tuesday, The Daily Beast reports. Catherine Garcia

A career official at the Internal Revenue Service who filed a whistleblower complaint over the summer, accusing at least one political appointee at the Treasury Department of trying to interfere with an audit of President Trump's tax returns, met with Senate Finance Committee staff members earlier this month, a congressional aide told The New York Times.

The whistleblower spoke with staffers for Sen. Chuck Grassley (R-Iowa) and Sen. Ron Wyden (D-Ore.), the chairman and ranking Democrat of the Senate Finance Committee. The whistleblower contacted the staff of the House Ways and Means Committee in July, claiming that political appointees were getting involved in the audit and putting pressure of some kind on senior IRS officials, the Times reports.

Details of the allegations remain unclear, and the House Ways and Means Committee is still reviewing the complaint. "We generally do not comment on whistleblower meetings, their contents, or even if they happened," Michael Zona, a spokesman for Grassley, told the Times. "Additionally, federal law prohibits the discussion of protected taxpayer information."

A person familiar with the matter told the Times the complaint does not directly implicate Treasury Secretary Steven Mnuchin, who has refused to comply with a congressional request to release six years worth of Trump's personal and business tax returns. Catherine Garcia

Mina Chang, the deputy assistant secretary in the State Department's Bureau of Conflict and Stability Operations, resigned on Monday, just a few hours after NBC News asked her spokeswoman about several false claims Chang made about her nonprofit and education.

In her resignation letter to Secretary of State Mike Pompeo, Chang said she was "unfairly maligned, unprotected by my superiors, and exposed to a media with an insatiable desire for gossip and scandal, genuine or otherwise." She also said her resignation is actually "a protest," and not "surrender, because I will not surrender my commitment to serve, my fidelity to the truth, or my love of country."

NBC News reported last week that she embellished her résumé, claiming among other things that she was a "graduate" of a program at the Army War College, when she actually just attended a four-day seminar. Chang also showed people a Time cover with her face on it, which a magazine spokesperson said was "not authentic."

Since that report, NBC News uncovered more falsehoods. Chang said in 2012, she won a CBS Humanitarian of the Year Women That Soar award, but it was actually a Dallas, Texas, honor, and the ceremony aired on a local CBS affiliate. Chang also said she earned a degree in international development from the University of Hawaii, but that program does not exist. She visited Afghanistan in 2015, saying it was a humanitarian mission facilitated through her nonprofit Linking the World, but NBC News reports the trip was paid for by a defense contractor, no aid was delivered, and she lied about the people she met. Read more about these tall tales at NBC News. Catherine Garcia

Pete Buttigieg is stuck on a polling rollercoaster.

The South Bend, Indiana, mayor and 2020 candidate got good news over the weekend when a new CNN/Des Moines Register/Mediacom poll put him at the top of the Democratic field in Iowa. But his high hopes promptly sunk with a new Quinnipiac University poll out Monday that shows him floundering in South Carolina.

Buttigieg racked up a respectable 6 percent support among likely voters in South Carolina, which will be the first southern state to hold a presidential primary next year. But when only black voters are taken into account, he earned the support of precisely 0 percent of them. Several other candidates also got negligible support among black voters, but Buttigieg has the highest percentage of white support in comparison and draws nearly all of his support from that demographic.

That dismal showing might have something to do with how 60 percent of black respondents said they hadn't heard enough about Buttigieg to decide if they found him favorable or not. Still, that total puts him around the midpoint for recognizability among all the candidates, meaning things haven't looked this bad for Buttigieg since his followers learned how to dance.

Quinnipiac surveyed 768 likely South Carolina Democratic primary voters via landline and cell phone from Nov. 13–17, with a margin of error of 4.8 percentage points. Kathryn Krawczyk