President Joe Biden and former President Donald Trump have sparred for months on the campaign trail, in interviews with reporters and through paid advertisements, creating phantom likenesses of each other to thrash and tear down.

Today, they will confront each other at a CNN debate in Atlanta, their first face-to-face meeting since their last onstage clash in 2020 and since Trump tried to overturn Biden’s subsequent victory at the polls.

The event, which airs at 6 p.m. PDT on CNN and other broadcast, cable and livestream outlets will give both of them a rich opportunity to deploy their attack lines and policy arguments before a national audience.

Here’s what we know about how each man will try to gain the upper hand.

Trump’s main lines of attack

Since he emerged as the presumptive Republican nominee, Trump and his campaign have focused on attacking Biden over immigration and the economy, which polls have found to be the top concerns for many voters.

Immigration

As he did during his political rise in 2016, Trump has made immigration a central focus of his campaign. He is all but guaranteed to blame Biden for a surge in illegal border crossings, calling the president’s policies overly permissive.

Trump claims that Biden’s approach to immigration has fueled violent crime — even though broader statistics do not bear that out — by citing several high-profile criminal cases that the authorities say involved immigrants in the United States illegally.

And as he stokes fear around immigration and tries to push the issue to the center of the election, Trump has falsely cast all those crossing the border as violent criminals or mentally ill. (Families with children make up about 40% of all migrants who have entered the United States this year.)

Looking to chip away at the coalition that elected Biden, Trump has claimed without evidence that people in the country illegally are taking the jobs of working-class Black and Hispanic voters, a situation for which he blames Biden.

Trump is also likely to attack Biden’s recent executive order on immigration, which prevents migrants from seeking asylum at the southern border when crossings surge. Trump has argued that the order will still encourage migrants to enter the country, and that it is too little, too late. He says, of course, that Biden needs to restore the strict border policies of the Trump presidency.

Biden’s rebuttal: With Republican help, Biden secured a long-sought border deal in Congress in February. But Trump quickly told his allies to torpedo the agreement, saying it would be poor politics to take immigration off the table. That gave Biden someone else to blame for the border crisis.

“The American people are going to know why it failed,” the president said at the time, a theme he could play up at the debate. He has also condemned Trump for saying that immigrants are “poisoning the blood” of the country, a phrase that echoes the language of Adolf Hitler.

The economy and cost of living

Trump and his campaign have consistently tried to harness negative feelings about the economy as a way of attacking Biden. In speeches, Trump frequently accuses the president of doing little to address increased food and housing costs. And he blames the Biden administration’s policies for contributing to inflation, arguing that increased government spending has led costs to skyrocket.

More recently, Trump has tried to link his message on immigration to the economy, arguing that Biden’s handling of the surge of migrants has driven up costs, an assertion he makes without citing clear evidence.

To bolster his argument, Trump frequently mentions the costs of gasoline and energy, which he claims were significantly lower during his administration and which he promises to address by increasing oil drilling.

He has frequently asked voters whether they were better off during his administration, pointing to the growing economy he inherited and that continued to grow while he was in office. But Trump often ignores the impact the coronavirus pandemic had on the U.S. economy in the last year of his presidency. Some economists say those effects were intensified by decisions he made that prioritized short-term economic growth over long-term stability.

Biden’s rebuttal: Biden returned to his hometown, Scranton, Pa., this year to emphasize his working-class roots and accuse Trump of being a puppet of plutocrats rather than a friend to normal people.

At the debate, the president is likely to adopt a similar “Main Street vs. Wall Street” approach, and to try to deflect Trump’s criticisms by highlighting his administration’s efforts to cut consumer costs on items like prescription drugs, bank fees and airline travel.

One big question for Trump: How much will he attack Biden’s mental and physical fitness?

On the campaign trail, Trump mocks Biden’s physical attributes, imitates his gait and speech, and argues that his rival is not mentally fit to be president. Such attacks are greeted with raucous laughter and cheers at Trump rallies.

Trump is likely to again contend that Biden is not fit to serve as president. But with Biden on the stage next to him, it is unclear how forceful Trump may be, or whether he will draw on the cartoonish impressions favored by his supporters. And any attention drawn to Biden’s slips could backfire if Trump makes gaffes of his own, as he has done repeatedly.

Biden’s main lines of attack

Biden and his campaign have signaled early and often that they plan to hammer Trump on abortion and democracy, two issues on which polls show that voters place more faith in the president than his predecessor.

Abortion rights

Democrats have honed a simple message on abortion: “Donald Trump did this.” And it doesn’t just apply to the overturning of Roe v. Wade.

Since that momentous Supreme Court decision in 2022, Biden and his allies have assailed Trump over abortion bans in Arizona and Florida, a court ruling in Alabama that imperiled the use of in vitro fertilization, and efforts to limit access to birth control.

“Let’s be clear. There’s one person responsible for this nightmare, and he’s acknowledged it and he brags about it: Donald Trump,” Biden said at a campaign event in Florida shortly before a six-week abortion ban went into effect there.

Protecting abortion access has strong appeal across party lines, as successful referendum efforts in red states have shown. And on the campaign trail, Biden has made a broader argument that Trump is seeking to take the country backward on equality for women, including by allowing state governments to monitor their pregnancies and prosecute them for having abortions.

Trump’s rebuttal: After sending mixed signals for months, Trump said in April that he believed abortion rights should be left up to the states and that he would not sign a federal ban if Congress put one before him. He falsely insists that most Americans were happy to leave abortion restrictions to the states, even as he has criticized stringent abortion bans. And he has ducked questions on mifepristone, a widely used drug in medication abortions.

Democracy

Few topics make Biden more animated than the threat he believes that Trump poses to American democracy.

The president has delivered speeches and his campaign has produced ads dedicated to the issue. He has attacked Trump for his role in the Capitol riot on Jan. 6, 2021, highlighted comments the former president made that he would not be a dictator “except for Day 1,” and accused him of encouraging political violence.

“Folks, what is at risk in 2024 are our freedoms, our very democracy,” Biden said in Detroit last month. “And that’s not hyperbole.”

On several occasions, the president has nearly cursed Trump by name or challenged him to a fight when discussing the vicious assault on Paul Pelosi, the husband of former Speaker Nancy Pelosi.

Trump’s rebuttal: Trump frequently argues that Biden talks about democracy in order to distract Americans from his policies. He then points the finger at Biden as a bigger threat to democracy, citing his contention — made without evidence — that the president orchestrated the four criminal cases against him and is weaponizing the Justice Department to prosecute and persecute him.

One big question for Biden: Will he call Trump a ‘convicted felon’?

Biden has generally been restrained when talking about Trump’s guilty verdict in his Manhattan hush-money case. Some Democrats have urged him to be more aggressive and loudly call out his opponent as a “convicted felon.”

Onstage in Atlanta, he will have the opportunity to highlight the conviction, although Trump is almost certain to repeat his false allegation that the president was behind the case.