The U.S. Food and Drug Administration authorized use of a third COVID-19 vaccine in the U.S., declaring the Johnson & Johnson vaccine safe and effective in adults 18 and older.

ABC News Chief Anchor George Stephanopoulos asked Dr. Anthony Fauci about hesitancy from people over its reported efficacy compared to others.

"What do you say to those who want to wait for Moderna and Pfizr?" Stephanopoulos asked.

"We have to get away from that line of thought," Fauci responded. "We have three highly efficacious vaccines. Safe and efficacious."

"If I went into a clinic and said we have JJ now, I would take the one that is available to me now," Fauci continued.

The White House released a letter Saturday from President Biden to the speaker of the House and president pro tempore of the Senate on the airstrike in eastern Syria, in his effort to keep Congress "fully informed, consistent with the War Powers Act."

"I directed this military action consistent with my responsibility to protect United States citizens both at home and abroad and in furtherance of United States national security and foreign policy interests, pursuant to my constitutional authority to conduct United States foreign relations and as Commander in Chief and Chief Executive. The United States took this action pursuant to the United States' inherent right of self-defense as reflected in Article 51 of the United Nations Charter," Biden wrote in the letter.

This comes following some bipartisan criticism the White House received over the decision to carry out the airstrike in Syria.

-ABC News' Molly Nagle

As Biden departed the White House to board Marine One Saturday afternoon, he was asked if he planned to punish Saudi Arabia’s crown prince following a U.S. intelligence report that concluded he ordered the killing of journalist Jamal Khashoggi.

Biden carefully teased an announcement but said it wouldn’t specifically pertain to Khashoggi’s murder.

He said, “there will be an announcement on Monday as to what we’re going to be doing with Saudi Arabia in general.”

The president then left the White House for Delaware.

On Friday the Office of Director of National Intelligence released a highly anticipated report on the death of Khashoggi, a Washington Post columnist and Saudi dissident who was murdered and dismembered at the Saudi consulate in Istanbul in Oct. 2018.

It revealed the U.S. intelligence community found Saudi Arabia’s Crown Prince Muhammad bin Salman approved an operation to capture or kill him.

The Saudi government has denied that that the crown prince was involved and instead blamed the death on a rogue team of government agents.

The killing has roiled the United States' longstanding ties with Saudi Arabia.

Biden said he spoke to King Salman on Thursday, one day before the report was released.

In honor of Black History Month, NASA astronaut Victor Glover welcomed Harris to the International Space Station via virtual chat.

A pre-recorded video shared on Saturday by NASA, shows Harris and Glover discussing several topics, including the legacy of human spaceflight, observing Earth from the space station and prepping for missions from the Moon to Mars.

Glover is a long-duration crew member on the International Space Station and is responsible for spacecraft systems and performance.

Can you have a battle for a party if only one side is invited to the fight?

The Conservative Political Action Conference has long been a colorful if sometimes unreliable gauge of the state of the movement that powers the Republican Party. This year … not so much.

With the GOP divided about its future, the biggest gathering of conservatives in the early days of the Biden presidency gets underway in Orlando, Florida, on Friday as a tribute to all things Donald Trump -- up to and including rehashed and baseless complaints about the election.

Featured speakers include Donald Trump Jr., Sens. Ted Cruz and Josh Hawley, Govs. Kristi Noem and Ron DeSantis, former Secretary of State Mike Pompeo, former Ambassador Richard Grenell and a wide range of pro-Trump House members and commentators. The former president himself, of course, speaks Sunday, in his first public speech since Jan. 20.

Not attending: Senators including Mitch McConnell, Ben Sasse or Mitt Romney; House members like Liz Cheney or Adam Kinzinger; former UN Ambassador Nikki Haley; former Vice President Mike Pence.

The theme of this year's CPAC is "America Uncanceled," though one speaker who had been booked was himself canceled for his extreme and anti-Semitic views.

But Trump and what he represents don't need to be "uncanceled" if they weren't canceled in the first place. It's hard to call it a comeback if the person and the movement in question never really left.

-ABC News Political Director Rick Klein