People in the United States head to the polls on Tuesday to vote for their congressional representatives in the 2022 midterm elections.

The word "midterm" refers to the fact that it comes directly in the middle of a presidential term. It is considered a bellwether for the sitting president, in this case, Joe Biden.

How does it work?

Americans cast ballots for who will represent their state in the capital of Washington, DC.

In the lower house of Congress, the House of Representatives, states have been broken up into 435 districts based on population. Because these representatives serve a term of two years, all 435 seats are being contested on Tuesday.

For the upper house, the Senate, two senators are elected from each of the 50 states. Because senators are elected on six-year staggered terms, every two years elections are held for about a third of the Senate. In 2022, 35 senate races are being contested.

Even with people voting in all 50 states, just a handful of battleground elections will likely determine whether Democrats or Republicans control the House of Representatives and Senate.

Additionally, 36 states are electing their governors. While governors do not directly impact politics in Washington, they have a great deal of influence on politics in their state and often on their state's representatives in Congress.

What is at stake for President Biden?

Democrats currently control the House of Representatives by only a handful of seats. In the Senate, there are 50 serving Republicans, 48 Democrats, and two Independents. Vice President Kamala Harris is also allowed to cast a tie-breaking vote as the president of the Senate.

If the Democrats lose control of one or both houses of Congress, Biden will unlikely be able to pass much, if any, legislation in the second half of his term due to long-standing Republican policy to block nearly all bills coming from a Democratic White House.

What are the issues?

Just as in the rest of the world, the United States is grappling with soaring inflation and the economic fallout of the COVID-19 pandemic.

Conservative politicians have also focused on making social issues like abortion, affirmative action, racial equity, and LGBT rights key issues in their campaigns.

For many Democrats, the most pressing issue on the ballot is democracy itself in the face of partisan gerrymandering and election fraud claims from Republicans. Many, however, have also made access to abortions a central plank of their platforms after the Supreme Court overturned a decision legalizing abortion.

When do we see a result?

With early and mail-in voting common in many states, counting the vote tallies could take some time. Some races will be called relatively quickly, while others could take days or weeks. Recounts can also be mandatory or requested in some districts where the election is particularly close.

The key state of Georgia, for example, will see its polls close at 7 p.m. EST (0000 GMT/UTC), whereas another battleground, Pennsylvania, will close at 8 p.m. EST (0100 GMT/UTC).

Important states to watch further west include Arizona and Nevada, with polls closing in those two states at 9 p.m. EST (2 a.m. GMT/UTC) and 10 p.m. EST (0300 GMT/UTC) respectively.   

According to the election analysis website FiveThirtyEight, most of the results would likely be in by 3 a.m. EST on Wednesday (0800 GMT/UTC), but some states like Nevada could take longer if their races are close.

wd, es/sms (AP, AFP, dpa, Reuters)