When Americans vote for the next president in November, they will in no small part be influenced by a barrage of major developments in 2023 that have set the stage for one of the most extraordinary races in U.S. history.

With no Republican contenders having gained substantial ground against Donald Trump, the former president appears poised to win the nomination and become only the second ex-president to appear on the ballot under the same party.

Most races end up as referendums on the incumbent president seeking reelection, according to Darrell West, the senior fellow of governance studies at the Brookings Institute, a center-right think tank.

That’s likely to be doubly true in 2024, he argued.

“It is a rare event when you basically have two incumbents on the ballot at the same time,” he said. “It’s unusual to have two people that served as president possibly facing off in the General Election, and that means it becomes a referendum not just on (Joe) Biden, but on Trump.”

The impacts of inflation, abortion, border security and the wars in Ukraine and Gaza are all already having ripple effects across the campaigns of both Trump and Biden.

Here’s a look at how those issues could play out for each candidate.

THE ECONOMY

Three-quarters of Americans say the economy is the biggest issue heading into next year’s election, according to a December poll from The Associated Press-NORC Center for Public Affairs.

With unemployment rates at historic lows and inflation down substantially since its pandemic-era peak at 9.1 percent in June 2022, most economists agree the U.S. economy has made a surprisingly robust comeback.

That’s good news for Biden – if he can sell it on the campaign trail, argued West.

“He has to talk about there being a good economy, all the infrastructure investments that he is making and policies that have helped the general public,” he said.

So far, Americans aren’t buying it. Nearly 70 percent of U.S. residents say the economy is getting worse, not better, according to a Suffolk University Sawyer Business School/USA TODAY poll from September.

That’s because even with inflation cooling, prices remain much higher compared to before the pandemic and continue to pinch people’s pocketbooks, according to John Mark Hansen, chair of the political science department at the University of Chicago.

“I think a big part of people’s complaints right now comes from experiencing the greatest inflation since the 1990s,” he said. “As that recedes into the past, that’s going to be good for Biden.”

Trump is capitalizing on Americans’ economic dissatisfaction. At a December rally in New Hampshire, he asked supporters if they felt better off five years ago or today.

“Not one thing has gotten better under crooked Joe Biden,” Trump said.

ISRAEL-HAMAS WAR

Three months into the war, few Americans are happy with how Biden is handling the bloody conflict between Israel and Hamas, according to a New York Times/Siena College poll released in December.

With Israelis still reeling from the Oct. 7 terrorist attack and thousands of Palestinian deaths in Gaza, voters are also sending mixed signals about how the U.S. should approach the confrontation.

That divide is especially stark between younger and older voters. Those age 65 and older sympathize with Israel more than Palestinians by a nearly 6 to 1 margin, while nearly half of registered voters age 18 to 29 (46%) sympathize more with Palestinians.

The poll also revealed the majority of young Americans are so repelled by Biden’s handling of Israel’s Gaza war that they are prepared to vote for the former president. Overall, Trump is winning 21 percent of young Americans who voted for Biden in 2020, but sympathize more with Palestinians than Israel.

That means Biden will have to make a concerted effort to somehow win back support from younger voters who oppose his policy toward Israel, according to Colin Seeburger, senior advisor at the Center for American Progress Action Fund, a nonpartisan think tank advocating for progressive policies.

“The humanitarian disaster that’s happening in Gaza is extremely difficult for young people to stomach,” he said. “I think that is going to necessitate the president, in his reelection effort, being especially intentional about doing outreach to young voters.”

Trump suggested in a November interview that the war between Israel and Hamas will just have to “play out.”

In October, he called for a reimplemented and expanded travel ban that would include Gaza and, if re-elected, said he would conduct “ideological screening” for immigrants and prevent Hamas sympathizers and Muslim extremists from entering the U.S., the Associated Press reported.

INDICTMENTS

Trump this year was indicted in four criminal cases totaling more than 90 felony charges. That hasn’t hurt his poll numbers in the GOP primaries. That may well change once the race enters the General Election, argued West with the Brookings Institute.

Although any criminal trials are unlikely to conclude next year, the specter of Trump winning the presidency and then being convicted could be a major turnoff for some voters, he explained.

“Convictions will matter a lot,” West said. “Especially with suburban voters. They’re very sensitive to issues of corruption and unethical behavior.”

Trump has used his indictments to attack Biden and Democratic prosecutors, arguing they have weaponized the justice system to attack a political opponent.

At the same time, House Republicans this month voted unanimously to open an impeachment inquiry into Biden related to concerns about his family’s business dealings – especially his son, Hunter Biden, who has been indicted on charges related to unpaid taxes.

Unlike Trump’s convictions, the impeachment inquiry is unlikely to have any impact on how people vote unless the investigation actually turns up evidence of wrongdoing, argued Hansen with the University of Chicago.

“I don’t think that’s going to sway anybody,” he said. “The people who are upset about Hunter Biden are the people who already don’t like Biden, so I don’t see it having that much effect on anything else.”

ABORTION AND THE BORDER

Both Biden and Trump have campaign ace cards in their pocket.

For the president and Democrats, abortion bans across the nation remain largely unpopular. The Ohio ballot initiative approved by voters in November that enshrined abortion access in the state’s constitution proved the issue had bipartisan support.

Now, the U.S. Supreme Court has agreed to take up a case that will determine future access to the widely used abortion pill, setting the stage for what could be another major blow to abortion access.

That could turn some Republicans against Trump, who has touted his three Supreme Court justice appointments that led to Roe v. Wade being overturned in 2022, argued Hansen.

“A lot of women aren’t very enthusiastic about (Trump),” he said. “I think the issue will probably have some considerable power still because he’s tied to it. He can’t talk about how proud he was of his three appointments to the bench and then say, well, they went too far.”

On the other hand, border security and immigration have become bipartisan thorns in Biden’s side.

A new Harvard CAPS-Harris Poll revealed just 38 percent of registered voters in December approved of Biden’s handling of immigration. That’s down from 46 percent who said the same in November.

Republicans have hammered Biden and his administration for the besieged southern border that this month saw a record number of migrant encounters in a single day. Overall, 2023 saw the most encounters with migrants in U.S. history, with 2.4 million coming across the Mexico border.

Biden has been negotiating with Republican lawmakers on immigration policy as part of the GOP deal tying border security to federal aid to Ukraine and Israel. The president will use those negotiations to attempt to gain ground with voters fed up with his immigration policies, noted West.

“Biden understands it’s a liability for Democrats, and he wants to make some changes that will reduce his vulnerability on that topic … because it’s likely to be a big issue in the election,” he said.