The top 10 things to watch for in the US midterm elections

Analysis - We know, you're sick of elections. But while everyone is gearing up for our general election Saturday, first we've got the US midterms to cope with.

The midterm election results will come starting about Wednesday midday NZ time, and Americans will vote on who will serve in Congress in the House of Representatives and Senate.

Currently Congress is held by Republicans, which has mostly accepted Republican President Donald Trump's agenda. But margins are tight and control of the House and possibly Senate could flip.

Here are 10 things to keep an eye on Wednesday:

1. The early races will tell us if there's a "blue wave."

The phrase "blue wave" means a strong result for the opposition Democrats. Traditionally, the party in the White House almost always does badly in midterm elections, which are seen as a referendum on the party in power.

American poll watchers seem to be almost unanimous in believing the Democrats will take control of the House of Representatives, while the smaller Senate is less certain.

There are so many congressional races for the lower House - 435 of them - that it may not be immediately clear who's ahead, but many congressional seats are considered noncompetitive and only a few dozen to be "swing" seats. All it will take is a couple of seats picked up for the House to swing to Democratic control. There are 35 of 100 Senate seats also up for election.

The first results will start rolling in on the US East Coast, which is 17 hours behind us, about 7pm Tuesday their time or 1pm Wednesday our time. Key states will be South Carolina, where Democrat Annie Andrews faces Sen. Darline Graham; North Carolina, where Democrat Governor Roy Cooper is poised to flip a Senate seat, and Ohio, where Democrat Sherrod Brown, a former senator, and incumbent Sen. Jon Husted are nearly tied in polls.

By 8pm ET (2pm NZT) polls will be closed in almost half the country, including another key Senate race in Maine, and by 9pm (3pm NZT) Texas and Michigan will be closed (more on them in a second). Polls will then start to close in far western states like California, Montana and Oregon on into the evening our time.

The final poll to close will be Alaska at 1am ET (7pm NZT), where another key Senate race is being held.

2. Be ready for 'stolen election' talk and legal challenges

That Alaska race has already been plagued by legal battles after a New York Times report found Democratic involvement in getting a Daniel J. Sullivan on the ballot as a 'spoiler' candidate against sitting Republican Senator Daniel S. Sullivan. Some claim the similar names could intentionally mislead voters.

There have been a flurry of pre-emptive lawsuits filed around the country by the Trump administration, which has targeted both California and Washington state in attempts to set aside ballots over unproven allegations of noncitizen voting.

Donald Trump has never conceded his loss to Joe Biden in the 2020 election and has made countless claims of voter fraud made against Republicans.

Whatever the actual results are in the midterms, expect the debate and rhetoric to continue for weeks and possibly months to come. It's even possible that some candidates could be refused to be seated when the new Congress begins in January if things really heat up.

3. Could Democratic wins affect New Zealand?

It's possible we may see ripple effects here. Trump's unpopular Iran war and global tariffs, including against New Zealand, have largely been pushed through by a compliant Republican Congress. If Democrats assume control of the House and Senate, there will be considerably more pushback against them.

However, more than many presidents, Trump flexes executive power, and many of his decisions have been made by executive orders and emergency declarations and he could also simply veto any legislation Democrats put through. A two-thirds congressional majority is required to overturn a presidential veto.

If the Republicans are thoroughly humbled on midterms day, it's possible the Iran war may be quickly wound up, although its impact on petrol prices in New Zealand is likely to linger.

4. Will negative campaigning backfire?

Political races have been dirty since time immemorial, but this year has seen several low points. Name-calling and racial and gender attacks have become commonplace.

Many voters say they are tired of negative campaigning. There have been attacks by both Republicans and Democrats, but the Republican attacks have received far more attention this year.

In Ohio, Republican governor candidate Vivek Ramaswamy put out an ad that featured Democrat Amy Acton's long-estranged elderly mother calling her a liar. Acton was the victim of childhood sexual abuse by her late stepfather, and had not spoken to her mother since 1978, when she and her brother were removed from her custody. Ramaswamy's controversial ad drew condemnation from both Republicans and Democrats and polls indicate his support has rapidly fallen since.

Trump himself has launched many attacks such as repeatedly using an anti-transgender slur against South Carolina Democrat Annie Andrews, who is cisgender.

The results on election day in some of these races may determine if voters have had enough of gutter tactics, or if they're just an accepted part of politics in 2026.

5. The Michigan Senate Race

One of the most combative races is between Republican Mike Rogers and progressive Democrat Abdul El-Sayed, who could become the first Muslim US senator. El-Sayed has increasingly become the focus of anti-Muslim attacks - Trump has called him a 'jihadist' and said metal detectors would be required at the Senate if he's elected. Polls have shown El-Sayed with a small lead.

The race got even more bizarre in the past day when his Democratic primary opponent, Congresswoman Haley Stevens, shocked watchers by endorsing Republican Rogers.

6. California tries to tax billionaires

California is pushing a referendum on a one-time 5 percent tax on all billionaires living in the state, the money from which would fund healthcare programs. Proposition 40 has drawn heavy coverage and a massive effort by super-rich Californians against it, while progressives like Senator Bernie Sanders have rallied for it. Polling has shown support for passing the tax may be slipping.

7. The Texas Senate race

Democrat James Talarico is facing Republican Attorney General Ken Paxton. Normally Texas is deep Republican red, but Paxton has been dogged by a series of scandals in his career including a fraud indictment and impeachment. The polls have shown a close race but Talarico has a bit of an edge. If he wins, he'll be the first Democrat senator elected in Texas since 1988.

8. Reports of suppression or possible violence

American politics has become increasingly charged with violence with incidents like the assassination of Republican activist Charlie Kirk and the murder of a Minnesota Democratic state representative and her husband.

If there are any attacks on voting places or protests over results that turn violent, it could turn into a grim situation that escalates quickly, much like the attack on the US Capitol in 2021.

9. Could it have ripples in global politics?

Worldwide, there seems to be a tug-of-war between the right and left which shows Trump's heavy influence on how politics is done. Recent elections in Brazil and Serbia showed a push back from the left and progressive activists, and while Israel's election last week remains too close to call, far-right leader Benjamin Netanyahu has seemingly lost much of his power in the results.

Academics and political deep thinkers will be spinning out reams of copy over what the midterms mean if Trumpism is rebuked - or if Republicans do far better than expected.

10. Most importantly, what will Trump do?

There's never quite been a president as unpredictable as Donald Trump, and it's hard to know how he may react to a major Democratic victory, or if he'll accept it.

Even if the Republicans suffer catastrophic losses, Trump will still be president. But his power may be curtailed, and it's possible there could be more investigations into alleged misconduct by his administration.

He also will inevitably suffer "lame duck" status in the final two years of his administration, as the 2028 presidential race basically begins the day after midterms.

* RNZ will live blog the US midterms from about midday on Wednesday with full results from us and our partners.