Effective Wednesday, the Department of Homeland Security will be led by an acting secretary, Kevin McAleenan. He will join acting Defense Secretary Patrick Shanahan, acting Interior Secretary David Bernhardt, acting U.N. Ambassador Jonathan Cohen, and acting Office of Management and Budget Director Russell Vough in President Trump's Cabinet. When Linda McMahon steps down Friday, the Small Business Administration will have an acting administrator, too.

The FAA, FDA, FEMA, ICE, and Secret Service are among the other agencies with no Senate-confirmed leader, and when McAleenan becomes acting DHS secretary on Wednesday, Customs and Border Protection administrator will be vacant, too. Shanahan, who is under investigation by the inspector general, has been acting defense secretary since Jan. 1, a record tenure for an acting Cabinet-level official, The Wall Street Journal reports. Trump hasn't even nominated a permanent candidate.

Trump seems to prefer this arrangement, telling reporters in January: "I like 'acting.' It gives me more flexibility." But the glut of acting officials in Trump's Cabinet is "prompting concerns from lawmakers in both parties about their accountability to Congress," the Journal reports. Congress isn't alone.

Trump's preference for "acting" appointees, "presumably because unconfirmed appointees are more likely to be loyal to him personally rather than to the Congress or Constitution," is yet "another assault on the law," Max Boot argues at The Washington Post. America's founders specifically "ordered George Washington to send nominations to the Hill at a reasonable pace," New York University professor Paul Light tells The New York Times, because they "rightly worried that presidents might use acting appointees to evade oversight and institutional prerogatives."

For Trump, "the real difference is avoiding Senate confirmation — either because the individuals he wants running these agencies can't be confirmed even by a Republican-controlled Senate, or because he's worried about the kinds of questions they'd have to answer and or concessions they'd have to make in order to be confirmed," adds University of Texas law professor Stephen Vladeck. And Congress, he notes, isn't powerless here. Peter Weber

Rudy Giuliani is "heartbroken" over recent comments made by his former associate Lev Parnas, who says he worked closely with Giuliani in Ukraine as part of an attempt to find damaging information about former Vice President Joe Biden and his son, Hunter.

Speaking to Fox News host Laura Ingraham on Monday night, Giuliani, President Trump's personal lawyer, said he was once "close to" Parnas, but was "misled by him." In October, Parnas and his business partner Igor Fruman were arrested and charged with campaign finance violations. Last week, Parnas made several public accusations against Giuliani, President Trump, and Attorney General William Barr, implicating all of them in the Ukraine scheme that is central to Trump's impeachment.

While Fruman did not cooperate with House impeachment investigators, Parnas did, turning over documents and other materials. Parnas said while he was in Ukraine trying to find dirt on the Bidens, he "wouldn't do anything without the consent of Rudy Giuliani and the president." Giuliani, a former U.S. attorney, refuted this, saying Parnas "in very large part did not tell the truth" and "lied stupidly."

Giuliani told Ingraham he would not discuss all of Parnas' accusations, but did deny ever talking about his Ukraine investigation with Barr and said Parnas' account of a meeting during a 2018 White House Hanukkah party was a lie. In November, CNN reported that Parnas told two people close to him that during the celebration, Trump let Parnas and Fruman know he wanted them to go on a "secret mission" to Ukraine to investigate the Bidens. Giuliani said this was "absolutely untrue," as they were never pulled into a private meeting.

Parnas posted a photo taken at the party on social media, showing him posing with Trump, Giuliani, Fruman, and Vice President Mike Pence. Trump has repeatedly denied knowing Parnas; Parnas has promised to keep releasing pictures of the two of them together. Catherine Garcia

The Senate will vote Tuesday on Senate Majority Leader Mitch McConnell's (R-K.Y.) proposed rules for President Trump's impeachment trial. If they approve the rules, the senators will be voting for some very late nights at the office.

McConnell's rules allow 24 hours for opening arguments over two sessions. If Trump's team and the House Democratic impeachment managers use all their time, it "could push testimony past midnight," The Washington Post reports. That would be a long time for senators to sit quietly without checking their phones, assuming they show up for the trial, but arguably worse for Supreme Court Chief Justice John Roberts.

After the opening arguments, senators would have 16 hours to question Trump's team and the House managers, then four hours to debate whether to allow witnesses and new evidence — and then, whether to allow the House's impeachment documents to be admissible as evidence. That's "a key difference from the impeachment trial of President Bill Clinton," the Post notes. "Though the material will be printed and made available to senators, it won’t be automatically admissible unless a majority of senators approve it."

All this may be a moot point, though, because McConnell's rules also allow Trump's team to move to dismiss the charges at any time after the rules are adopted, so 51 senators could end the trial right away. Fox News congressional reporter Chad Pergram isn't impressed.

University of Texas constitutional law professor Steve Vladeck suggests McConnell might not have had impartial justice in mind.

"All 53 Republican senators are expected to support the rules as written by McConnell," the Post reports. Peter Weber

The Islamic State's new leader is Amir Mohammed Abdul Rahman al-Mawli al-Salbi, one of the terrorist organization's founding members, intelligence officials told The Guardian.

Last October, ISIS leader Abu Bakr al-Baghdadi was killed in a raid in Syria, and officials said Salbi replaced him just hours after his death. Born to an Iraqi Turkmen family, Salbi has a background as an Islamic scholar, and came up with the ISIS religious rulings authorizing the enslavement of Iraq's Yazidi minority. Salbi met Baghdadi in 2004, when both were detained by U.S. forces at Camp Bucca in Iraq.

There aren't many founding members of ISIS left, and the group doesn't have nearly as many fighters as it did during its peak in the mid-2010s. ISIS no longer controls vast swaths of Iraq and Syria, but they are still behind assassinations and roadside bombings in northern Iraq, a senior Kurdish official told The Guardian. There are rural networks that "remain very much intact," the official said. "After all, ISIS members in Iraq still receive monthly salaries and training in remote mountainous areas. That network allows the organization to endure, even when militarily defeated."

Salbi's whereabouts are unknown, but intelligence officials believe it's likely he is near Mosul, Iraq. There is a $5 million bounty on his head. Catherine Garcia

An attorney for Lev Parnas, the indicted associate of Rudy Giuliani, sent a letter to Attorney General William Barr on Monday, requesting the he recuse himself from Parnas' criminal case.

Parnas was arrested last October and charged with campaign finance violations. In the letter, which was also filed in New York federal court, attorney Joseph Bondy said Barr has a conflict of interest and asked that a special prosecutor from outside the Justice Department handle Parnas' case. "Federal ethics guidelines bar federal employees from participating in matters in which their impartiality could be questioned, including matters in which they were personally involved or about which they have personal knowledge," Bondy wrote.

Bondy cited several reasons why Barr should recuse himself, noting that the reconstructed transcript released by the White House of President Trump's July phone call with Ukrainian President Volodymyr Zelensky shows Trump telling Zelensky that Barr could help him facilitate an investigation into former Vice President Joe Biden. Last week, Parnas told MSNBC host Rachel Maddow that Barr knew about efforts in the Ukraine to dig up dirt on Biden, saying, "Attorney General Barr was basically on the team." Read Bondy's letter here. Catherine Garcia

Everyone knows that Dr. Martin Luther King Jr. fought for social justice, racial equality, and an end to poverty, but White House counselor Kellyanne Conway thinks he also wouldn't stand for President Trump's impeachment.

When asked by NBC News on Monday how Trump was observing Martin Luther King Jr. Day, Conway said he was getting ready to head to Davos for the World Economic Forum, then managed to connect the late civil rights leader to Trump's impeachment. "I don't think it was within Dr. King's vision to have Americans dragged through a process where the president is not going to be removed from office, is not being charged with bribery, extortion, high crimes, or misdemeanors," she said. "And I think that anybody who cares about 'and justice for all' on today or any day of the year will appreciate the fact that the president now will have a full throttle defense on the facts, and everybody should have that."

Trump and Vice President Mike Pence both visited the Martin Luther King Jr. Memorial in Washington, D.C., and Trump also tweeted that it was "so appropriate" that "exactly three years ago today, Jan. 20, 2017, I was sworn into office." His impeachment trial will formally begin on Tuesday. Catherine Garcia

A new CNN poll out Monday shows that 51 percent of Americans think the Senate should vote to convict and remove President Trump from office during his upcoming impeachment trial.

Meanwhile, 45 percent believe the Senate should vote against conviction and removal. Almost 69 percent say the trial should include testimony from new witnesses who did not appear before House impeachment investigators. Republicans are split on whether there should be witnesses in the trial — 48 percent are in favor of new witnesses, while 44 percent are not.

This was the first major national phone poll conducted since the articles of impeachment were sent to the Senate and Lev Parnas, the indicted Rudy Giuliani associate, appeared on cable news shows and implicated Trump in the Ukraine pressure campaign. The poll was conducted by SSRS from Jan. 16 to 19, and has a margin of sampling error of plus or minus 3.4 percentage points. Catherine Garcia