Former Vice President Joe Biden on Tuesday suggested Congress might have to launch impeachment proceedings if President Trump blocks their investigations.

Biden spoke with Good Morning America about the release of Special Counsel Robert Mueller's report, saying parts of it are "left undone" and that Congress must investigate.

"And if, in fact, they block the investigation, they have no alternative than to go to the only other constitutional resort they have, [which] is impeachment," Biden said.

For now, Biden said his job is to "make sure [Trump is] not back as president of the United States of America."

Prior to the release of the Mueller report, Biden had said Democrats should not impeach Trump, saying in October, "I hope they don't. I don't think there's a basis for doing that right now," Politico reports.

But while Democratic leaders had held off on calling for impeachment after the release of the Mueller report, The Washington Post on Monday reported that the Trump administration's lack of cooperation with their investigations, including Attorney General William Barr's threat not to show up to testify before Congress, some Democrats are beginning to rethink that — and it sounds like Biden may be one of them. Brendan Morrow

Fox News' Chris Wallace is once again calling out pro-Trump spin on the network, even slamming one contributor on air in a tense exchange.

Wallace spoke Monday about the explosive New York Times report that former National Security Adviser John Bolton in his upcoming book writes that President Trump told him he wanted to continue withholding aid to Ukraine until officials helped with investigations into former Vice President Joe Biden and his son.

Speaking on Fox, Wallace said that to get a sense of how "big" this news is, one only has to look at Trump supporters "spinning like crazy that it isn't big news." This only reinforces that this is a "really important development in this case," Wallace said, per Mediaite.

Wallace went on to observe that it's now "much, much less likely" that Trump's impeachment trial will wrap up on Friday without any witnesses being called, as the Bolton news makes it "awfully hard" for Republican senators on the fence about calling witnesses to vote against doing so.

Not long after, Wallace got into an argument with contributor Katie Pavlich about the idea of calling Bolton to testify after she claimed that in "every impeachment beforehand, the witnesses that were called had been called in the House before being brought to the Senate."

"In the Clinton impeachment, they'd been called by the independent counsel," Wallace told her, adding, "Get your facts straight!" Brendan Morrow

The Senate would probably want to hear from a firsthand witness in President Trump's impeachment trial. But Sen. Josh Hawley (R-Mo.) isn't sure where you'd find one.

Despite a Sunday report indicating former National Security Adviser John Bolton will say in his book he spoke directly to President Trump about Ukraine, a number of GOP senators still don't want to hear from him in Trump's impeachment trial. Hawley is among those lawmakers, giving new reasoning to his anti-Bolton argument Monday by questioning whether Bolton even was a firsthand witness to Trump's alleged crimes.

Bolton's book reportedly describes how Trump talked to his former adviser about withholding security assistance from Ukraine until it agreed to investigate former Vice President Joe Biden. And with Republicans largely complaining impeachment witnesses testified to the House based on "hearsay," one would think they'd like to hear from someone who was actually in, as Bolton's book title so aptly puts it, "the room where it happened." Kathryn Krawczyk

Details are still emerging about the circumstances surrounding the helicopter that killed Los Angeles Lakers legend Kobe Bryant, his 13-year-old daughter Gianna, and seven others including the pilot, but the flight was reportedly granted special approval to fly in challenging weather conditions.

Fog was thick Sunday morning in the Los Angeles area when the helicopter took off and made its way toward Gianna Bryant's youth basketball tournament, but air traffic control at Burbank airport gave the pilot Special Visual Flight Rules clearance, allowing the aircraft to enter Burbank's airspace.

A Federal Aviation Administration official said air traffic control's approval would not have extended to Calabasas, where the helicopter crashed. By that point, the official said, it would have been up to the pilot to determine if conditions were appropriate to continue or transition to instrument flight rules.

Witnesses near the site of the crash described conditions as so foggy that people had trouble driving, per The New York Times. "I couldn't see anything, not even a silhouette," said Scott Daehlin who heard the sound of the helicopter flying low before making impact with a nearby hillside. "My first thought was what in the world is a helicopter doing out here in this fog?" Read more at The New York Times. Tim O'Donnell

Immigrants may now face visa and citizenship restrictions based on their past or hypothetical future use of public benefits.

In a 5-4 decision Monday, the Supreme Court allowed the Trump administration's public charge rule to take effect nationwide. The rule would restrict immigrants who are considered or could later be considered a "public charge" from gaining legal status, and comes despite multiple prior courts striking down the rule.

The Monday decision came along ideological lines, with the court's four liberal justices dissenting from the majority opinion. U.S. District Judge George Daniels previously struck down the rule, mirroring critics who've called it a "wealth test" for immigrants by saying the rule is "repugnant to the American dream." Daniels had also placed an injunction on the rule's implementation due to a likely appeal to the Supreme Court, and the higher court lifted that injunction Monday.

The theory of a public charge rule has existed for decades, but wasn't codified until the Trump administration drew up this rule in 2017. The rule targets people attempting to legally immigrate into the U.S. by assessing if they have used public benefits such as food stamps in the past, or if they might use them after gaining legal status. If the government determines a person is or could become a "public charge," they can block a person from getting a visa, green card, citizenship, and other forms of legal status. Kathryn Krawczyk

More than two decades after his investigation of former President Bill Clinton, Ken Starr while defending President Trump on Monday asked how it is we came to live in the "age of impeachment."

The former independent counsel spoke as part of Trump's legal defense team during the Senate's impeachment trial, making the argument that presidential impeachments are being invoked too often in recent years.

"The Senate is being called to sit as the high court of impeachment all too frequently," Starr said. "Indeed, we're living in what I think can be aptly be described as the age of impeachment. ... How did we get here?"

Starr went on to decry the fact that impeachment has become not a "once in a century phenomenon" but rather a "weapon to be wielded against one's political opponent." He added the Senate should return to a time when "impeachment was truly a measure of last resort."

Given Starr's role in the last presidential impeachment, CNN's John Avlon asked "who thought that Ken Starr was the best choice to make the case for bipartisan process and against impeachment," while MSNBC's Garrett Haake observed, "Ken Starr, arguing against overly-political, thinly-predicated impeachment is enough to make a certain generation of Democrats' heads explode." Brendan Morrow

Ever since leaks from former National Security Adviser John Bolton's forthcoming book made their way to the public, the odds of the Senate calling him as a witness to take the stand in President Trump's impeachment trial appear to have gone up. Speculation about other witnesses has also entered the fold. One of those potential witnesses is acting White House Chief of Staff Mick Mulvaney, who famously admitted to Trump's Ukraine quid pro quo during a press conference last year.

But through his lawyer, Mulvaney denied knowing anything about the revelations in Bolton's books or ever having a conversation with Trump about freezing Ukrainian military aid in exchange for announcing investigations into Trump's domestic political opponents.

At first glance, it seems like Mulvaney and his counsel are taking a proactive approach should the Senate issue a subpoena, as well as launching an effort to discredit Bolton. But CNN's Jake Tapper pointed out that Bolton may not have alerted Mulvaney to his concerns about the Trump administration's Ukraine policy because he reportedly thought Mulvaney played a central role in its formation. Tim O'Donnell