The leader of the agency responsible for approving the immunization, Dr. Stephen Hahn, maintained Sunday that the authorization was made as quickly as possible, despite claims to the contrary by President Donald Trump.

In an interview with Fox News Saturday, Trump, after seeming to take credit for the speed of the vaccine's development, said that the Food and Drug Administration could have authorized the shot for emergency use "last week."

"We do not feel that this could have been out a week earlier," Dr. Stephen Hahn, the FDA commissioner, said on ABC's "This Week." "We went through our process. We promised the American people that we would do a thorough review of the application and that's what we did. We followed our process."

Full story here.

- Adam Kelsey

New Jersey will begin giving its health care workers the COVID-19 vaccine Tuesday morning at University Hospital in Newark, the state's governor said on ABC's "This Week" Sunday.

"The first batch of 76,000, split the majority toward health care workers but a good slug toward our long-term care residents and staff, and then with each ensuing week those are the two top priorities," Gov. Phil Murphy, D-N.J., told "This Week" co-anchor Martha Raddatz.

"It'll take us a number of weeks as you can imagine to work through the entire populations in both of those groups, but it's gonna be a big day on Tuesday morning in Newark," he added.

Full story here.

- Adia Robinson

Another Cybersecurity and Infrastructure Security Administration official is stepping down at the end of the week.

Matt Masterson, a top official at CISA, who was instrumental in securing the 2020 election, confirmed on Twitter he's leaving for a position at Stanford University.

Masterson tweeted that he can't wait to work with the staff and students at Stanford.

The news comes after former CISA Director Chris Krebs was fired via tweet by President Donald Trump in November. The president bristled at Krebs' assertion that there was no evidence of fraud in the election.

Bryan Ware, another of Krebs' top lieutenants at the agency, stepped down just before his boss was fired last month.

-ABC News' Luke Barr

Sparks flew Saturday as justices on the Wisconsin Supreme Court questioned Jim Troupis, a lawyer for the Trump campaign who argued that the state should throw out 220,000 votes from Dane and Milwaukee counties.

Justice Jill Karofsky lit into Troupis under 10 minutes into the hearing, accusing the campaign of trying to disenfranchise Black voters.

“In your lawsuit, what you have done here, is you have targeted the vote of almost a quarter of a million people, a quarter of a million people not statewide in Wisconsin, but … in two of our 72 counties, two counties that are targeted because of their diverse populations, because they're urban; I presume because they vote Democratic. This lawsuit, Mr. Troupis, smacks of racism,” Karofsky said.

Troupis and the Trump campaign argued that the court should throw out four categories of votes they said did not follow state statute, including absentee ballots delivered in person at a “Get Out the Vote” event in a park, ballots applied for with a specific mail-in form, ballots missing the address of a signed witness and ballots applied for by “indefinitely confined voters.”

As the hearing continued, Justice Rebecca Dallet once again homed in on the demographic makeup of Milwaukee and Dane counties, noting that the Trump campaign was “not asking … to throw out votes in any other county.” Troupis became defensive, telling the justices that the Biden campaign could have asked for the recount to encompass the whole state.

“You made a statement, as if this was a choice based on criteria that simply are not true,” Troupis said before Dallet jumped on him.

“Who chooses which counties to ask for a recount?” Dallet asked.

Troupis responded “the candidate,” to which Dallet noted the president “had a choice when it came to the recount of which counties. … He chose to only challenge votes in the most urban, non-white, largest counties that voted overwhelmingly for Joe Biden.”

-ABC News' Alex Hosenball and Matt Mosk

While the U.S. Supreme Court has twice refused to hear pro-Trump challenges to the 2020 elections, a federal judge in Wisconsin on Saturday joined the chorus of rulings against Trump in his effort to use the courts to invalidate Biden’s victory.

“This Court has allowed plaintiff the chance to make his case and he has lost on the merits,” wrote U.S. District Court Judge Brett H. Ludwig, a Trump appointee. Ludwig noted that the president had asked “that the Rule of Law be followed,” and he declared in response: “It has been.”

The ruling comes just one day after the U.S. Supreme Court refused to consider an election challenge brought by the Texas attorney general contesting the way elections were run in four states, including Wisconsin. Trump had called that case “the big one,” because he thought it held the best hopes for him of re-litigating the 2020 contest in court.

This latest ruling marks nearly 50 losses for the president  in cases brought by him and his supporters since election day. In Wisconsin, where Biden won by more than 20,000 votes, Trump asked for 221,000 absentee and mail-in ballots to be excluded on the grounds they were collected in ways not laid out by the state legislature. And the president argued that the legislature should be afforded the chance to select an alternate slate of electors.

Ludwig’s 23-page opinion gave wide latitude to Trump -- finding that the president had standing to file his election challenge and was not too late to raise his concerns about the way the election was conducted. But the outcome of the case was the same as rulings in other battleground states -- that Biden’s victory was attained legally and should not be thrown to a legislature to upend.

The president, Ludwig wrote, “has not proved” that state election officials violated his rights. “To the contrary, the record shows Wisconsin’s Presidential Electors are being determined in the very manner directed by the Legislature, as required by Article II, Section 1 of the Constitution.”

Ludwig further noted that if he followed the demands set out in Trump’s lawsuit, “any disappointed loser in a Presidential election, able to hire a team of clever lawyers, could flag claimed deviations from the election rules and cast doubt on the election results. This would risk turning every Presidential election into a federal court lawsuit over the Electors Clause.”

The Trump campaign has not yet responded to requests for comment.

At the moment the federal ruling was handed down, the Wisconsin Supreme Court was hearing arguments on a separate challenge to a recount of votes in the state, which had failed in a lower court.

-ABC News' Matthew Mosk and Alex Hosenball