President-elect Biden to announce several key Cabinet positions

President Trump on Monday did not concede, instead saying in a tweet: "I believe we will prevail." He then added, "I am recommending that Emily and her team do what needs to be done with regard to initial protocols and have told my team to do the same."

The Biden-Harris Transition Executive Director Yohannes Abraham said in a statement: "Today’s decision is a needed step to begin tackling the challenges facing our nation, including getting the pandemic under control and our economy back on track. This final decision is a definitive administrative action to formally begin the transition process with federal agencies. In the days ahead, transition officials will begin meeting with federal officials to discuss the pandemic response, have a full accounting of our national security interests, and gain a complete understanding of the Trump administration’s efforts to hollow out government agencies."

President-elect Biden has scheduled a news conference Tuesday to discuss some of his cabinet picks.

The GSA letter was sent as Michigan certified their election results Monday showing Biden as the winner of that swing state.

"I think today she may have sent it because of the Michigan decision which pretty much makes it impossible for the President to find any route to winning the election," said Henry Brady, dean of the UC Berkeley Goldman School of Public Policy.

Brady says the GSA administrator was in a difficult position of having to recognize the winner before the Electoral College officially votes and without a concession by any candidate.

"That's what happened in 2000, a decision wasn't made until actually after Gore's concession speech which was December 14th," said Brady.

This election, the Trump campaign and allies have lost at least 27 court cases seeking to challenge election results.

Biden won 306 electoral college votes compared to 232 for President Trump. Biden also received more than 6 million more votes than President Trump in the nationwide popular vote.

Over the weekend in federal court, Judge Matthew Brann dismissed a Trump campaign lawsuit trying to block certification of Pennsylvania's votes. Judge Brann said the Trump campaign was trying "to disenfranchise almost seven million voters."

Judge Brann also offered blunt criticism stating, "One might expect that when seeking such a startling outcome, a plaintiff would come formidably armed with compelling legal arguments and factual proof of rampant corruption... That has not happened."

A growing number of Republicans suggested it's time for President Trump and his legal team to acknowledge the results.

"At some point, you exhaust those possibilities. I think the President has reached that point in Pennsylvania," said Republican Senator Pat Toomey of Pennsylvania.

"You have an obligation to present the evidence. The evidence has not been presented," said former New Jersey Governor Chris Christie.

President Trump and his campaign, though, later sent donors four emails stating unproven accusations of election fraud, "We cannot let the Democrats STEAL this Election from your all-time favorite President." The emails called for supporters to send money to an Election Defense Fund.

"I certainly think Mr. Trump is raising a lot of money this way and he's also keeping his base fired up," said Brady.

The Biden transition team has been moving forward. President-elect Joe Biden met with dozens of mayors Monday, discussing the pandemic preparations needed to hit the ground running on January 20th.

The Biden transition team also is selecting Cabinet members.

Bay Area economist Janet Yellen, a former U.C. Berkeley professor and Federal Reserve Chair is expected to be nominated to become the first female Treasury Secretary.

"She's one who believes in stimulating the economy. As Treasury Secretary, you'd believe she'd be very strongly in favor of large fiscal stimulus packages," said Brady.

Yellen is among a diverse group of nominees.

The nominee for Director of National Intelligence is Avril Haines, a CIA alumna and the first woman ever nominated for that position.

Former Deputy Secretary of Homeland Security Alejandro Mayorkasas could be the first Latino and immigrant to become the Homeland Security Secretary.

The list also includes former members of the Obama administration.

Linda Thomas-Greenfield is the nominee for U.N. Ambassador. Thomas-Greenfield has more than three decades of experience as a diplomat.

The nominee for Secretary of State is former Deputy Secretary of State and Biden aide Antony Blinken.  

Former Secretary of State John Kerry is being tapped for Climate Change Envoy.

Jake Sullivan is the choice for National Security Advisor. Sullivan was Biden's national security adviser during Biden's terms as Vice-President.

Jana Katsuyama is a reporter for KTVU.  Email Jana at jana.katsuyama@foxtv.com and follow her on Twitter @JanaKTVU or Facebook @NewsJana or ktvu.com.