A group of about 20 hardline Republican have brought Washington to a standstill by torpedoing party favourite Kevin McCarthy’s bid to become speaker of the US House of Representatives across successive rounds of voting this week.

The House cannot perform any of its vital functions – including overseeing national security, investigating government misconduct and passing legislation – until its presiding officer is in place.

The continued chaos has also exposed the sharp rifts that have developed within the Republican party.

Many in the group are members of the House freedom caucus, a collection of some of the most staunchly rightwing Republicans in the lower chamber of Congress.

Pennsylvania’s Scott Perry is the chair of the caucus. He played a key role in Donald Trump’s attempt to overturn the results of the 2020 presidential election via the attempted installation of a new acting attorney general, according to the House committee that investigated the matter.

Perry is the only member of the group from above the Mason-Dixon line that traditionally separates the southern United States from the north.

The rest of the group is dominated by southerners – mainly from Texas, Florida or Arizona – and most represent districts that voted solidly for Trump in the 2020 election. Most were endorsed by the former president in last November’s midterms.

Second-term representative and freedom caucus member Byron Donalds emerged from relative obscurity when he received some 20 votes in multiple rounds of voting in the speakership election.

One of only four Black House Republicans, the hard-right representative from Florida is a native of Brooklyn, New York, and son of a single mother, and has often spoken on the campaign trail of overcoming life adversities.

Chip Roy has been negotiating with McCarthy’s team and – unlike his peers on the freedom caucus – has expressed a willingness to come to an agreement with the California Republican.

He is widely known in Congress for obstructionist procedural motions and dissatisfaction with the current legislative rules. Unlike many of his peers, he was sharply critical of Trump and many of his Republican colleagues over their handling of the 6 January 2021 attack on the Capitol.

The other rebels do not appear beholden to the former president, though – McCarthy’s vote share actually dropped after he received Trump’s endorsement on the second day of the standoff in the House of Representatives.

While some Republicans oppose McCarthy because they say he has proved an obstacle to their rightwing agenda and will make for a weak foe to the Democratic president, Joe Biden, others just seem to dislike him personally, whatever policies he espouses.

A number of “Never Kevins” – notably Matt Gaetz of Florida, Andy Biggs of Arizona and Lauren Boebert of Colorado – have been clear that no amount of compromise will change their minds on opposing the California congressman.

A born-again Christian who represents a sprawling district in western Colorado, Boebert is widely known for her unwavering support of gun rights and her confrontational tactics.

She has expressed support for the QAnon conspiracy theory, which holds that there is a secret, pedophilic, leftist elite that holds immense sway over global institutions and policy.

Boebert is one of the top fundraisers among House Republicans and brought in more than $7m for her reelection bid, to eke out one of the closest wins of the November midterms.

Biggs bemoaned the lack of selflessness and principle in modern politics in a tweet posted before the first round of voting, when he stood as a symbolic opponent to his fellow Republican.

“This is what a McCarthy speakership would look like and would put our country last.”

He was among the lawmakers who most aggressively promoted Trump’s false claims that his 2020 election loss to Joe Biden was the result of fraud.

Matt Gaetz is one of McCarthy’s most vocal opponents, another prominent gun control opponent and a close Trump ally.

The son of a prominent Florida Republican, he has claimed falsely that the 6 January attack on the US Capitol was instigated by far-left extremists. He was also a top fundraiser in the caucus, raising more than $6m for his reelection bid.

Well over half of the rebel group have explicitly denied the results of the last presidential election, amplifying Trump’s false claims that it was rigged, reflecting a now-dominant creed among House Republicans, two-thirds of whom voted against certifying the 2020 vote.

A handful are newly elected but the majority earned their stripes in the ultra-conservative Tea Party movement that grew out of opposition to president Barack Obama from 2010.

As well as being known for fiscal austerity, the movement has its origins in a form of libertarianism that rejects “business as usual” and prides itself on producing agents of chaos who revel in their outsider status and ability to disrupt the consensus politics of the political elite.

Reuters and Agence France-Presse contributed to this report