WILLIAM BRANGHAM: A blockbuster antitrust trial# kicks off today between Meta and the Federal Trade## Commission.

The government alleges the company,# which was then called Facebook, monopolized the## social media market when it purchased competitors# Instagram in 2012 and WhatsApp two years later.

Stephanie Sy is here to explore the# potential impact of the trial -- Stephanie.

STEPHANIE SY: William, the trial, which# is expected to last up to two months,## could have major implications for big tech.

If the social media giant loses, it# could be forced to break itself apart## and sell off both of those popular# platforms, including Instagram,## which is projected to make up more than# half of the company's ad revenue this year.

To help us understand the issues, we're# joined now by Rebecca Allensworth,## professor of law at Vanderbilt University.

Rebecca, thanks so much for# joining the "News Hour."

This is a case that has been years in the making.# And we know what the major battle lines already## are.

The government alleges that Meta used a# strategy to buy or bury other start-ups, killing## competition.

Does the FTC have a strong case on# that basis, that Meta has violated antitrust law?

REBECCA ALLENSWORTH, Vanderbilt University# Law School: So, it has a strong case on that## part of the case, about whether or not# the acquisition suppressed competition.

The weakest part of its case is actually whether# or not Facebook is a monopoly in the first place,## whether or not Meta is a monopoly.# It has to prove both monopoly power## and an act of exclusion that allowed# it to maintain that monopoly power.

But the problem for the government# is that there are potentially other## competitors that we could see# as major players in this space.

STEPHANIE SY: Meta's lawyer today called the## case a grab bag that was -- quote --# "at war with the facts and the law."

We saw -- or we heard that Mark# Zuckerberg himself testified today.## What are the strongest points of the defense and# do they have to do with the fact that so much has## changed in the social media landscape since# this case was first brought four years ago?

REBECCA ALLENSWORTH: This is not a grab# bag.

This is definitely a strong case.

So,## on the part of the government,# it's a very strong case.

As far as what are Meta's best arguments,# those have to do with market power and market## definition.

But their weakest arguments, the# strength of the government's case really comes## from these e-mails that Mark Zuckerberg# wrote about the acquisitions at the time,## where he really kind of laid out what we would# call in antitrust like an anticompetitive intent.

STEPHANIE SY: Mark Zuckerberg wrote in that# 2008 e-mail: "It is better to buy than compete."

But I want to go back to this point about the# changing landscape.

Some critics of the FTC's## case point out that so many other competitors have# sprung up, namely TikTok, in the last four years.## Does the government have more of an uphill battle# just given how quickly the landscape has changed?

REBECCA ALLENSWORTH: You're right to point# out that the landscape has changed a bit.

But,## at the same time, I think that the# government has a strong argument that,## in fact, Facebook, Meta is still a# monopolist and they have monopoly power.

And that's because, while people do sometimes# consume other social media platforms, they do## spend time on other platforms, they look at ads# on other platforms, they still view Facebook,## Facebook Blue, the product we all associate# with Facebook, as not having substitutes.

It's really one of the only ways# to stay in touch with your friends## and family.

The real question is, can# Facebook make their product worse and## not lose customers?

And we know that# they have done that over the years.

STEPHANIE SY: This is one of several# antitrust cases against big tech that## started years ago under the first Trump# administration and then, of course,## continued under Biden.

And we# have spoken about the landmark## ruling last year which found Google was# monopolizing the Internet search sphere.

Rebecca, do you see momentum gaining to rein in## big tech with antitrust law?

Is this# the case to continue that momentum?

REBECCA ALLENSWORTH: I do see that momentum.# And it's not just these cases.

It comes from## some of the merger cases too, even# the ones that the government lost.

There were all kinds of theories# that were endorsed in those cases,## those little data points that courts are# ready to shift the momentum of antitrust## away from laissez-faire and start really# taking big companies to task for doing## things that are anticompetitive,# especially digital monopolies.

Now, the big one here obviously is the# verdict in the search case.

But I think## we're probably about to get another win# for the government on another Google case,## another monopolization case in the ad# tech case.

And I don't know exactly## how that will go, but I think there's# a good chance the government will win.

And I think, if the government wins# this third case, that's a real kind## of tidal wave of liability# for these digital platforms.

STEPHANIE SY: How much does the political# landscape in Trump 2.0 potentially impact## the outcome here?

We know that Mark Zuckerberg# has been lobbying hard for a settlement.

And,## of course, he was at President# Trump's inauguration this year.## It's been a bipartisan issue# largely at least until now.

Do you see that changing?

REBECCA ALLENSWORTH: It's impossible# to know what this means and how it## will matter.

It's just too unpredictable.

We# don't know what happened in those meetings.

I think what we know is that Trump views# the FTC as being under his control,## which is legally incorrect and not the# way the agency was designed.

And yet## he fired the two Democrats on the FTC in# a strong signal that this is my agency,## this is my policy.

We also know, of course,# that Mark Zuckerberg has cozied up to him## and trying to take advantage of that control# that Trump is trying to wield over the FTC.

But whether it's in it -- whether there's# something in it for Trump to actually do this,## whether he actually will interfere on behalf# of Mark Zuckerberg and Meta more generally,## is totally unclear to me.

There would have# to be something in it for Trump and the Trump## administration.

And it was his administration# that brought this case in the first place.

It also seems, like if he was going to# do it, he would do it before now.

So## it's just a real mystery what will# happen there.

It's quite possible.

STEPHANIE SY: OK, something to keep our eye on.

Rebecca Allensworth with# Vanderbilt University, thank you.

REBECCA ALLENSWORTH: Thank you.