Republican presidential candidate Donald Trump speaks Monday in Anderson, S.C. (Ken Ruinard/AP)

Businessman Donald Trump continues to maintain his hold atop the contest for the Republican presidential nomination, with retired neurosurgeon Ben Carson keeping a clear grip on second place and the rest of the large field scrambling to find a foothold, according to a new Washington Post-ABC News poll.

Trump’s support has held steady during the past month; 32 percent of Republican and GOP-leaning voters back him, compared with 33 percent in early September. The numbers suggest that mixed reviews of his performance in the second Republican debate in California did little to dampen the enthusiasm of his supporters. Carson, meanwhile, has ticked up from 20 percent to 22 percent.

The only other Republican in double digits among registered Republicans and Republican-leaning independents is Sen. Marco Rubio of Florida, at 10 percent. That represents a three-point increase in a month, within the poll’s six-point margin of sampling error.

Former Florida governor Jeb Bush runs fourth at 7 percent, followed by Sen. Ted Cruz of Texas at 6 percent and former Hewlett-Packard chief executive Carly Fiorina at 5 percent. No one else registers above 3 percent among Republican-leaning voters.

Donald Trump seen as the GOP's best shot in 2016

The gap between Trump and Carson at the top and the rest of a field comprised mostly of elected and former elected officials underscores again the unusual nature of the Republican presidential race and a conservative electorate registering its disapproval with status quo politics and politically experienced insiders.

A majority (57 percent) of Republicans and GOP-leaning independents say they want the person who succeeds President Obama to be someone from outside the political establishment, rather than a candidate with experience working inside the system. Democrats rate political experience more highly than outsider status.

Trump faces a more challenging period ahead as voters increasingly begin to measure candidates as potential commanders in chief. Rivals chasing him face equally daunting tests as they seek to make themselves the principal alternative to the billionaire businessman, deciding whether to take him on directly or hope that he brings himself down.

At this time four years ago, the Republican contest featured a procession of candidates who rose to the top, only to fall away. Trump has kept his lead for more than three months, amid predictions that his provocations, insults and barbed comments about his rivals would eventually cause him to fall.

Trump holds an even bigger advantage when Republicans are asked who they think will win the nomination. Forty-two percent name Trump, 15 percent say Carson and 12 percent say Bush. A nearly identical percentage say they think Trump has the best chance among the GOP field of winning a general election.

Trump is rated best on five of eight attributes. His most significant calling card in the GOP race appears to be the perception of him as a leader, with 47 percent saying they see Trump as the strongest leader in the GOP field. That compares with 12 percent who name Bush and 11 percent who name Rubio.

The former reality TV star also scores highest on the question of who among the Republicans is best able to deal with immigration issues. Trump has taken a hard-line stance on immigration, including calls for deporting the millions of undocumented immigrants already in the country.

Rubio and Bush run second and third to Trump, although their positions have been more open to finding a solution to the presence of the country’s undocumented residents. Beyond immigration, Republicans see Trump as closest to them overall on the issues, followed by Carson.

Trump also leads his rivals on the question of which candidate best understands the problems “of people like you.” Carson is second on this question, with Rubio and Bush behind him.

Carson is seen as the most honest and trustworthy among the Republican candidates, followed by Trump. Carson, who is a low-key campaigner, also rates ahead of others on the question of who has the personality and temperament to serve effectively as president, followed by Trump, Bush and Rubio.

Bush’s strongest attribute is experience, with three in 10 saying he has the best experience to be president. Bush, however, scores lowest among six candidates tested on how well he wears with voters on the campaign trail.

Forty-seven percent of Republicans say the more they hear from Bush, the less they like him, while 41 percent say they like him more — a net negative rating of minus-six percentage points. Trump has a net positive rating of plus two points. Carson fares best on this question, with a net positive rating of 46 points followed by Rubio, at plus 23.

In terms of candidate support, Trump scores better than his rivals among virtually all demographic groups. He is 10 points more popular among Republican men than women. Trump is 16 points more popular among whites without college degrees than with white college graduates.

The Post-ABC poll was conducted Oct. 15-18 among a random national sample of 1,001 adults, including land-line and cellphone respondents. Full results have a margin of sampling error of plus or minus 3.5 percentage points. The error margin is plus or minus six points among the sample of 364 Republican-leaning registered voters.

Peyton M. Craighill contributed to this report.