So, 2018 picked up where 2017 left off with eye-popping palace intrigue mixed with the widening net of the Department of Justice's Russia investigation.

The week's highlights included tabloidlike, tell-all details from the new book Fire and Fury: Inside the Trump White House with explosive on-the-record and blind quotes from White House insiders. The president reacted by eviscerating his former chief strategist Steve Bannon, accusing him of losing his mind and branding him "Sloppy Steve."

Some details in Michael Wolff's book, which among other things casts doubt on the president's competence and mental stability, have been questioned not only by the White House, but also by reporters. Wolff, though, says he has hours of audio recordings and defended the top-selling book in an interview with NPR's All Things Considered on Friday.

"When you write a book like this, people regret what they said to me," Wolff said. "What they say to any reporter who they relax with and they forget who they're talking to. I have sympathy for that, and I think the natural response is to say, 'Oh my god, I didn't say it.' But I will tell you, they said it."

And then there was a bombshell report from The New York Times about how Justice Department special counsel Robert Mueller's Russia probe may be targeting the president for obstruction of justice over his attempts to stop the Attorney General Jeff Sessions from recusing himself from the investigation. The Times reported that Trump dispatched White House counsel Don McGahn to try to stop Sessions from going through with it. It didn't work, and Trump was furious. He believed, according to the Times, that the attorney general's job was to protect the president.

For his part, Trump sees it all as politically motivated, tweeting Friday:

It was a remarkable week and start to the new year that could portend a politically consequential 2018.

Here's a day-by-day look back at the week:

Monday

  • President Trump's first tweet of the year threatens to cut off aid to Pakistan.

Tuesday

  • Sen. Orrin Hatch, R-Utah, announces his retirement, triggering speculation that Mitt Romney will run for the seat. (Trump had gone to Utah late last year to try to encourage Hatch to run for re-election.)
  • Trump tweets that his nuclear button is bigger than that of North Korea's Kim Jong Un.
  • Trump also touts in a tweet that there were zero commercial aviation deaths in 2017. Trump can hardly claim credit, AP fact-checks. There haven't been any in the U.S. in four years.
  • The co-founders of Fusion GPS, the firm that commissioned the Steele dossier of opposition research about Trump, speak out in an op-ed in The New York Times. It was headlined: "The Republicans' Fake Investigations."

Wednesday

  • Doug Jones of Alabama and Tina Smith of Minnesota are sworn in as new Democratic senators, and Minnesota Sen. Al Franken's resignation becomes official. The GOP majority in the Senate shrinks to 51-49.
  • Excerpts from Fire and Fury by Michael Wolff are released; Trump blasts former chief strategist Steve Bannon, who is quoted in the book. "When he was fired," Trump says in an official statement, "he not only lost his job, he lost his mind."
  • Trump's private lawyers issue a cease-and-desist letter to Bannon, saying he violated a nondisclosure agreement.
  • Trump dissolves his election integrity commission. The commission, which had been plagued by controversy, formed after Trump claimed he lost the popular vote to Hillary Clinton in the 2016 election — by some 3 million votes — because of fraud. No evidence has ever been found of voter fraud on that scale, and several states balked at the commission's requests. Commission Vice Chairman Kris Kobach vows to take the investigation inside the Department of Homeland Security.
  • Former Trump campaign chairman Paul Manafort files a lawsuit against the Justice Department challenging the scope of the Mueller investigation. Manafort faces multiple criminal charges including conspiracy against the United States and has pleaded not guilty.

(By the way, 10 years ago on this day, Barack Obama's path to the presidency took a giant leap forward with his win in the Iowa caucuses.)
Thursday

  • Attorney General Jeff Sessions rescinds Obama-era marijuana guidelines, three days after recreational marijuana was legalized in California.
  • A tie is broken in the last remaining Virginia state delegate race by pulling the name out of a bowl. The Republican, David Yancey, was named the winner, keeping control of the statehouse in Republican hands. The Democrat, Shelly Simonds, may ask for a recount.
  • The United States suspends most security assistance to Pakistan.
  • Trump makes an appearance on video screens flanking press secretary Sarah Huckabee Sanders.
  • The Dow closes above 25,000 for first time.
  • Trump threatens to sue Wolff and the publisher, Henry Holt; Henry Holt moves up publication date to Friday.
  • The Times report on the Sessions recusal is released just before 8 p.m. ET.
  • Trump talks by phone with Mitt Romney, as Romney considers a Senate run from Utah.

Friday