Voters are choosing more than their parties' presidential nominees tonight. In five Super Tuesday states, they're also deciding on candidates for statewide and local offices. Several consequential judicial elections are being held tonight, for positions on state supreme courts in Alabama, Arkansas and Texas, and on the Criminal Court of Appeals in Texas.

In Arkansas, nonpartisan general elections are being held to fill two vacancies on the Supreme Court, creating a game of musical chairs among the sitting justices that could potentially accelerate the already-conservative court's rightward shift. Chief Justice Dan Kemp is stepping down, and three of the four candidates running to replace him are already sitting on the court, while another sitting justice is angling to move to a different open seat on the court. The shuffle could leave two vacancies that would allow conservative Gov. Sarah Huckabee Sanders to name replacements to finish their terms.

Alabama's Supreme Court Chief Justice Tom Parker, who recently made waves nationally with a ruling that frozen embryos used for IVF are children, is also retiring because of the state's mandatory retirement age. Two candidates are running for the Republican nomination to replace him: sitting Associate Justice Sarah Stewart (who had to give up her seat to run for the top slot) and former state Senator Bryan Taylor. While Stewart joined the 8-1 majority opinion in the IVF case and both candidates have defended the decision, Taylor has claimed that Stewart is the "most liberal" justice on the all-Republican court, and received a huge influx of outside spending from conservative anti-abortion group Fair Courts America. Whoever wins will likely face (and defeat) Democrat Greg Griffin>) in the general election.

In Texas, Supreme Court Justice John Devine is facing a primary challenger who has questioned his ethics, but a bigger political feud is playing out in other races. Allies of Republican Attorney General Ken Paxton are funding primary challengers to three Criminal Court of Appeals judges who ruled against him in a voter fraud decision, limiting his power to prosecute those cases. And as Nathaniel noted earlier, Paxton, who had been accused of abusing power to protect a political donor, has also endorsed primary challengers against 34 of the 60 Republican legislators who voted to impeach him last year.

—Monica Potts, 538

NASA astronauts Jasmin Moghbeli and Loral O'Hara voted in today's primaries ... from outer space. The two have been orbiting the earth aboard the International Space Station for roughly six months, but both still found a way to exercise their civic right.

—Cooper Burton, 538

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Astronauts cast votes from International Space Station

NASA astronauts Jasmin Moghbeli and Loral O'Hara voted in Tuesday's primaries to exercise their civic rights from outer space.

Four years ago, Super Tuesday was one of the last big news events before the declaration of the COVID-19 pandemic. Just days later, the U.S. and much of the world would go into lockdown in an effort to stem the virus's spread.

As Julia noted, in 2020, Super Tuesday marked the point when the Democratic Party consolidated behind Biden. But I think that, partly because of the pandemic, even close observers of American politics don't appreciate just how unlikely Biden's Super Tuesday comeback was.

This year in Iowa, Ron DeSantis's second-place finish with 21 percent of the vote was enough to effectively end his campaign. But in 2020, Joe Biden came in fourth in the Iowa Democratic caucuses.

Similarly, pundits have viewed Trump as the prohibitive favorite in the 2024 race since at least his New Hampshire victory, when he topped Haley 54 percent to 43 percent. In 2020, however, Biden's New Hampshire performance was far weaker than Haley's this year — he finished fifth in the state, winning just 8 percent of Democratic primary voters.

But in a very short period four years ago, Biden resurrected his campaign. He convincingly won South Carolina on Feb. 29 thanks to his strength with Black voters, who had been few and far between in Iowa and New Hampshire.

Then, both Amy Klobuchar and Pete Buttigieg endorsed Biden in the run-up to Super Tuesday, consolidating the more moderate side of the Democratic Party against Bernie Sanders. That, in turn, positioned Biden for a decisive Super Tuesday win that made him the front-runner in short order. While Sanders won California, Biden won 10 states, including Massachusetts, North Carolina and Texas.

What explains the dramatic change in Biden's fortunes over a few short days leading up to Super Tuesday in 2020? In his book "Learning from Loss," political scientist Seth Masket emphasizes the Democrats' overwhelming aim to defeat Trump, and to find a candidate who gave them the best chance of doing so. At the time, there was evidence that Biden ran better against Trump than other Democrats. Many Democrats were willing to follow the cues of party leaders about their most competitive candidate, and in doing so, they vaulted Biden to the nomination.

In this year's GOP primary, there's some evidence that Haley may be a stronger general election nominee than Trump. But in a late-November survey I conducted via YouGov, GOP voters overwhelmingly saw Trump, not Haley, as their strongest candidate, and there's no evidence that's changed. So on the Republican side, the grounds for a similarly sudden Super Tuesday switch just aren't there.

—Dan Hopkins, 538 contributor

Super Tuesday has over 40 years of history that are deeply entwined with a bunch of issues in the presidential nomination process. The term "Super Tuesday" was first used in 1980 but was promoted by Democrats in 1988 as a deliberate effort to give an advantage to more moderate candidates. This was a direct reaction to the idea that the party's 1984 nominee, Walter Mondale, had lost to Ronald Reagan because he was too liberal. This strategy didn't really work out, though, and Democrats ended up nominating another northern liberal, Michael Dukakis.

In other words, this early attempt at a Super Tuesday brought some of the disadvantages of a regional primary, reducing the amount of attention on individual states and pressuring states to move their primaries earlier without really strengthening the influence of the region. Another drawback was that, by trying to enhance Southern influence by holding contests early, Super Tuesday also contributed to the "front-loading" problem", or the issue of having too many delegates selected at the beginning of the primary calendar.

Over time, Super Tuesday has taken on other significance as an important turning point in the race. As party politics scholar Caitlin Jewitt noted, in 2016, everyone thought that Sen. Ted Cruz needed to do well on Super Tuesday, which was heavily concentrated in Southern states where he needed to rack up wins — and when that didn't happen, it was a significant blow to his candidacy. For Biden in 2020, Super Tuesday marked the point when the party consolidated behind him. And in 2008, Super Tuesday made it clear that the Democratic nomination was a real race between Hillary Clinton and Barack Obama, as neither one scored a decisive victory.

It's hard to know exactly how this will play out in 2024. Republicans don't have the same ideological history with the big primary day as Democrats do. But the potential for a turning point in the race is there: Because so many delegates are at stake today, unless Haley wins a significant share of them, it may not make sense for her to stay in the race after tonight.

—Julia Azari, 538 contributor