What are the midterms and who's being elected?
These elections are for Congress, which is made up of two parts - the House of Representatives and the Senate.
These votes are held every two years and when they fall in the middle of the president's four-year term of office, they are called the midterms.
Congress makes nationwide laws. The House decides which laws are voted on while the Senate can block or approve them, confirm appointments made by the president and, more rarely, conduct any investigations against him.
Each state has two senators, who sit for six-year terms. Representatives serve for two years, and represent smaller districts.
All the seats in the House of Representatives are up for election in November, alongside one-third of the Senate.
Several major states also have elections for their governor and local officials.
Who might win?
The Democratic Party has held the majority in both the House and the Senate for the past two years. That's been helpful for President Joe Biden to pass the laws he wanted.
But the Democrats hold that power over the Republicans by very narrow margins, which makes for a tight contest. Polling suggests the Republicans might take the House but the Democrats could hold on to the Senate.
Of the 435 seats in the House, most are safely held by either party, with just 30 currently a toss-up between the two. Suburban areas around cities in states like Pennsylvania, California, Ohio and North Carolina will be key.
In the Senate, it now looks like four of the 35 seats being contested realistically could go either way. The pivotal races here are in Nevada, Arizona, Georgia and Pennsylvania.
What are the big issues?
At the start of 2022, it looked like the biggest issues were going to be immigration, crime and the cost of living, which are vote-winners for conservative Republicans.
That changed in June when the US Supreme Court overturned national abortion protections, giving a boost to the Democrats, who support women having the right to choose and have made that central to many campaigns.
But as the immediate impact of that decision fades, Republicans are trying to turn the focus back to inflation, immigration and violent crime.
What effect will the results have?
Midterms often serve as a verdict on how the president is doing, and the party that holds the White House tends to lose seats.
That's a worry for President Biden, whose approval rating among voters has been running at less than 50% since last August.
If the Democrats hang on, President Biden will be able to keep going with his plans on climate change, to expand government-run healthcare programmes, protect abortion rights and tighten gun control.
If the Republicans take control of either chamber, they will be able to effectively grind that agenda to a halt.
They will also be able to control investigatory committees, so they could end the inquiry into the 6 January 2021 attack on the US Capitol by supporters of former President Donald Trump - although its work is set to finish by the end of the year.
They might also launch new investigations into more conservative-interest topics - like the Chinese business dealings of Joe Biden's son or the sudden withdrawal of US troops from Afghanistan.
It would be harder for Mr Biden to make new appointments, including to the US Supreme Court. Republican dominance would also hamper his foreign policy - particularly help for Ukraine, as it battles Russian invasion.
In return, President Biden could wield his veto pen and block conservative laws on abortion, immigration and taxes.
The result? Gridlock until the next presidential and congressional elections.
How does this shape the 2024 presidential race?
The midterms could give us a clue as to who might be in the running to be the Republican presidential candidate for 2024.
If candidates backed by Mr Trump do badly, he's less likely to get backing from the Republican party to run for president again. In Florida and Texas, Republican governors Ron DeSantis and Greg Abbott hope re-election will spur them on to a bid for the White House.
If the Democrats can hold on to power in Michigan, Wisconsin and Pennsylvania, that should give them some confidence as they build their 2024 campaign to get President Biden re-elected. (With inputs from BBC)
KABUL, August 31 : The Taliban joyously fired guns into the air and offered words of reconciliation on Tuesday, as they celebrated defeating the United States and returning to power after two decades of war that devastated Afghanistan.
The last of 6,000 US troops who oversaw a desperate evacuation effort flew out of Kabul airport on Monday night, ending the war that has diminished the United States' status as a superpower.
Taliban fighters quickly swept into the airport and fired weapons into the sky in jubilation, an astonishing return after US forces invaded in 2001 and toppled the hardline Islamists for supporting Al-Qaeda.
"Congratulations to Afghanistan... this victory belongs to us all," Taliban spokesman Zabihullah Mujahid told reporters hours later from the runway of the airport. Mujahid said the Taliban's victory was a "lesson for other invaders".
However the Taliban have repeatedly promised a more tolerant and open brand of rule compared with their first stint in power, and Mujahid continued that theme.
"We want to have good relations with the US and the world. We welcome good diplomatic relations with them all," he said.
Many Afghans are terrified of a repeat of the Taliban's initial rule from 1996-2001, which was infamous for their treatment of girls and women, as well as a brutal justice system.
- Terror threat -
The withdrawal came just before the end of an August 31 deadline set by President Joe Biden to call time on America's longest war -- one that ultimately claimed the lives of more than 2,400 US service members.
The early finish followed a threat from the regional offshoot of the Islamic State group, rivals of the Taliban, which was seeking to attack the US forces at the airport.
Thirteen US troops were among more than 100 people killed when an IS suicide bomber late last week attacked the perimeter of the airport, where desperate Afghans had massed in the hope of getting on board an evacuation flight.
More than 123,000 people were evacuated from Kabul aboard the US-led airlift operation, which began just after the Taliban swept into the capital on August 14.
Biden said he would address the nation on Tuesday in Washington, as his critics continued to savage him for his handling of the withdrawal.
"We can't fight endless wars, but the scope & consequence of Biden's failure here is staggering," Republican Senator Rick Scott said.
"President Biden has brought great shame on the American people," added congressman Richard Hudson.
Biden's top diplomat, Secretary of State Antony Blinken, was able to offer little more than stern words for the Taliban.
"Any legitimacy and any support will have to be earned," Blinken said, as he announced the United States had suspended its diplomatic presence in Kabul and shifted its operations to Qatar.
- Airport uncertainty -
All eyes will now turn to how the Taliban handles its first few days with sole authority over the country, with a sharp focus on whether it will allow other foreigners and Afghans to leave the country.
Blinken said a small number of US citizens remained in the country -- "under 200" but likely closer to just 100 -- and wanted to leave.
Many thousands of other Afghans who had worked with the US-backed government and fear retribution also want to get out.
Western allies have voiced heartbreak in recent days that not all Afghans who wanted to flee could get on the evacuation flights.
The UN Security Council adopted a resolution Monday, requiring the Taliban to honour a commitment to let people freely leave Afghanistan in the days ahead, and to grant access to the UN and other aid agencies.
But they did not agree to call for the creation of a "safe zone" in Kabul, as envisaged by French President Emmanuel Macron.
Talks are ongoing as to who will now run Kabul airport. The Taliban have asked Turkey to handle logistics while they maintain control of security, but President Recep Tayyip Erdogan has not yet accepted that offer. It was not immediately clear which airlines would agree to fly in and out of Kabul.
- Civilian deaths -
The regional Islamic State-Khorasan (IS-K) group had posed the biggest threat to the withdrawal after it carried out the devastating suicide bombing outside the airport last week.
On Monday, they also claimed to have fired six rockets at the airport. A Taliban official said the attack was intercepted by the airport's missile defence systems.
And in an echo of the tragedies of civilian deaths that plagued the war and cost the United States local support, a US air strike in Kabul targeting a purported IS car bomb on the weekend appeared to have killed children.
The United States said Sunday it had carried out a drone strike against a vehicle threatening the Kabul airport.
Members of one family told AFP they believed a fatal error had been made, and that 10 civilians were killed.
"My brother and his four children were killed. I lost my small daughter... nephews and nieces," Aimal Ahmadi told AFP.
US President Joe Biden is heading to Dover Air Force Base to attend the “dignified transfer” of the remains of 13 US troops who were killed in the Kabul attack.
