As US faces likely Trump-Biden rematch, global stakes couldn't be higher

American voters across the country went to the polls yesterday on Super Tuesday, the largest voting event in the US primary elections. Immigration and border security, the economy, abortion and democracy were among some of the top issues on voters’ minds.

With a second showdown looming between Democratic incumbent President Joe Biden and Republican nominee Donald Trump in November, and with the two candidates holding vastly different positions on key issues, the US's future looks gravely uncertain.

Voting took place in 15 states – Alabama, Alaska (for Republican primary voters only), Arkansas, California, Colorado, Maine, Massachusetts, Minnesota, North Carolina, Oklahoma, Tennessee, Texas, Utah, Vermont and Virginia – and one territory, American Samoa (for Democratic primary voters only).

Tuesday was also the last day for Democrats in the state of Iowa to send in their primary ballots by mail, with Republican primary voters having voted in their state’s caucus in January.

Following Super Tuesday results, Republican contender Nikki Haley is expected to suspend her campaign, leaving Trump to easily clinch the conservative party's presidential nomination.

There exists a massive gulf between the two candidates’ positions on critical issues and challenges, both domestic and global. Thus the potential policy changes come November, including the impact on societal cohesion and the US’s standing in the world, as well as the wars in Ukraine and Gaza, could not be more pronounced.

Barring unforeseen events, Biden is almost certain to win the Democratic nomination, so the most likely scenario is a repeat showdown between the two candidates from 2020.

While both candidates have taken tough stances on irregular immigration, it is clear that a Trump victory would be disastrous for those who also wish to enter the country legally. Trump has stated, particularly after the Hamas attacks against Israel on October 7, that he would enforce ideological tests for those wanting to enter the US, as well as deport students and non-citizens who take part in pro-Palestinian protests.

The outcome of the US election will also undoubtedly have global ripple effects. Three issues in particular would be affected by a Trump presidency: the Middle East peace process, US support for NATO and US support for Ukraine.

On all three issues, Biden has held a traditionalist stance, although his unconditional support for Israel during its months-long onslaught of Gaza has drawn fierce domestic and global criticism.

Still, Biden has been applying pressure on Israel to minimise civilian casualties in its Gaza campaign and let in more life-saving humanitarian assistance. The Biden administration is also eager to restart normalisation talks between Israel and Saudi Arabia.

They see this as the key to sustainable peace in the region, as well as an incentive for Israel to eventually recognise a Palestinian state.

On the other hand, a second Trump presidency would see the US increasing support for Israel's actions and no expectation to put pressure on extremist elements within Israel, such as illegal settlers in the occupied West Bank and their supporters in the right-wing government.

Earlier this month, Trump stated in a Fox News interview that he would encourage Israel to "finish the problem" in Gaza, alluding to the fact that if he were president, he would not be holding back Israeli actions in the enclave, nor presumably in the West Bank.

After all, it was Trump who, as president, moved the US Embassy from Tel Aviv to Jerusalem in 2018, a previously unthinkable action given US fears that it would ignite massive unrest across the Arab world.

While Trump would also seek to incentivize Saudi Arabia to normalise relations with Israel, he would likely try and push the Saudis to do so with fewer conditions than they are currently insisting on at least publicly.

For example, he might prod them to accept a vague commitment to a "peace process" rather than an explicit recognition of a Palestinian state. The previous Trump administration completely sidelined the Palestinians altogether when discussing Arab-Israeli peace, and is unlikely to change its course of action in a second term. Conversely, the Biden administration sees the two-state solution as a key foreign policy goal.

Biden also rallied global support for Ukraine and NATO following Russia’s offensive in Ukraine and continues to push for US and European support for Ukraine within the context of his role as a champion of democracy worldwide.

A second Biden term would undoubtedly mean continued US support for Ukraine under a unified US-Europe umbrella, whereas Trump has made no secret of his disdain for NATO.

He has threatened to pull the US out of the alliance and criticised NATO allies who do not pay their agreed-upon share of 2 percent of their GDP on defence spending. In recent comments that set alarm bells ringing across Europe, Trump said that, if re-elected, he would encourage Russia to "do whatever the hell they want" to countries that don't pay their share to NATO.

Global trade is another issue that the two candidates have vastly differing views on, particularly with China. A second Trump presidency would almost certainly mean a defiant stance against the Asian power in the form of additional tariffs and trade barriers, which would impact the economies of both countries as well as negatively affect international markets.

Yet, as Super Tuesday highlighted the issues most important to voters, another revelation became ever more clear: many voters are not happy with the choice they will be asked to make in November, believing that neither candidate has the "mental acuity" to lead.

Still, their decision will affect the fate of both American democracy and the global geopolitical landscape.