Attorney General Bill Bar has taken the unusual step of authorizing federal prosecutors to investigate possible irregularities in the presidential election.

His move follows days of attacks on the election process from Donald Trump so far without any credible evidence.

Meanwhile, US President elect Joe Biden has started assembling his team to prepare for taking over the presidency at the end of January.

David Willis reports Joe Biden is wasting little time preparing for his assent to the White House, announcing the lineup of a task force to deal with an issue that could dominate the early days of his presidency.

The coronavirus on holding his first call as president elect with a foreign leader, Canada's prime minister Justin Trudeau.

As that call was taking place.

Donald Trump, who since the election result was announced, has only been seen on the golf course, was firing his defense secretary, Mark Esper, terminating him.

In the words of the president, it's thought other high profile administration officials could soon follow Mr Esper out the door.

The president has yet to concede the election, and his team is mounting legal challenges in multiple states.

The top Republican in the U s Congress told lawmakers Mr Trump was fully entitled to contest the outcome.

The core principle here is not complicated.

In the United States of America, all legal ballots must be counted.

Any illegal ballots must not be counted.

The process should be transparent or observable by all sides and the courts air here toe work through concerns.

And after meeting with Mitch McConnell, the attorney general, Bill Bar, announced that the U.

S Justice Department would be involving itself in investigations into voter fraud that, as the president said about attacking his former ally, Fox News and other media outlets, accusing them of tampering with the election by broadcasting polls that he said had Bean inaccurate.

Fox later cut off the White House press secretary as she sought to explain Donald Trump's refusal to concede.

You don't take these positions because you want an honest election.

You don't oppose an audit of the vote because you want an accurate count.

You don't oppose our efforts at sunlight and transparency because you have nothing to hide.

You take these positions because you are welcoming fraud and you are welcoming illegal voting.

Well, I just think we have to be very clear that she's charging the other side is welcoming fraud and welcoming illegal voting.

Unless she has more details to back that up, I can't in good countenance continue showing you that it all points to a messy and rancorous transition period with less than 10 weeks to go before Inauguration Day.

David Wallace, BBC News LOS Angeles Well, let's get more on this probe into alleged voting irregularities now from Ciara Torres Spellissy, who's professor of law at Stetson University.

Joining us now FROM some Petersburg, Florida Thank you very much for talking to us and BBC news today.

Your reaction, first of all, to what William Barr is doing escalating the legal challenges from state level two federal level.

What is this going to mean for the transition?

So the Department of Justice always has the ability to look into allegations of fraud in federal elections.

But pardon me, Uh, so far, there is no evidence of widespread fraud, Okay?

And in fact, in this letter to prosecutors, William Barr, you know, urges the idea that you know, they shouldn't be investigating fanciful claims and doesn't mention any evidence off irregularities himself.

Ah, previous guest we spoke to said that that was just to provide him with some kind of cover and that in fact, he is trying Thio basically enable, in his words, President Trump t kind of delay the transition.

I mean, would you agree with that assessment?

Trump seems to want to litigate a win that he couldn't get at the ballot box s.

So far, the American courts have dismissed almost all of his cases.

So I'm I'm confident in the courts.

I am less confident in what Attorney General bar is up.

Thio.

Okay, you're confident in the courts.

Does that mean the Supreme Court as well?

If it was to get to that level, I think so, Um Number one It may not get to that level because the U.

S.

Supreme Court has control over its docket, which means that it doesn't have to take all of its cases.

And traditionally it has turned away 90 to 95% of the cases that asked for certain, which is asking for the Supreme Court to hear the case Now.

Joe Biden, at the moment is is going about his business in the way one would expect a president elect to do But with Donald Trump yet to concede on these legal challenges continuing, how is that actually affecting the transition compared to what would be happening in, say, more usual circumstances?

Well, there's nothing in the Constitution that requires the loser to concede, but I think it would be much better for the country if Trump conceded.

And it would be much smoother for the transition.

If Trump conceded.

It means, though, that the Biden Harris team that they're not getting access to certain federal funding and certain information, intelligence information, for example that they would be expecting to be able to to see right now, yeah, it's down to a G s a, um, bureaucrat who has not signed a particular letter in her defense.

G esa for anyone who doesn't know what the NSA is, that's the the General Civil Service Accounting Administration, I think.

Yes.

Yeah, I did.

I did look that up last night just to be absolutely sure.

So, basically, they have to sign something to say that the transition is happening effectively.

Exactly.

And because of these ongoing court cases, uh, it may not be entirely clear to that bureaucrat that we have a clear winner.

Okay, What happens then?

If this goes on for quite a few more weeks, we get to the date with the Electoral College meets Donald Trump, Potentially is refusing to accept that he has lost, hasn't conceded.

There's never been a situation like this has there.

So you know what actually happens is is he eventually going to vacate the White House?

Or it's someone close to him, perhaps a member of his family going to persuade him that that's what he has to do.

If none of these cases come to anything and no evidence has been presented so far, so constitutionally, the man who gets 270 Electoral College votes will be the next president.

That does not look like it's going to be Donald Trump.

So whether he concedes or not, he cannot stay in the White House.

Okay, it's gonna be very interesting.

Thio.

Watch how the next few weeks unfold there.

Professor Sarah Torres Spellissy from Stetson University.