Nick Ayers, pictured at right, chief of staff to the vice president, is no longer in the running to replace John Kelly as chief of staff for the president. A White House official says that Trump and Ayers could not agree on Ayers' length of service.

WASHINGTON — Wanted: Top aide to most powerful leader in world. Chief qualification: Willing to take the job. Must also be prepared to tolerate regular undermining by boss and risk of steep legal bills. Post-employment prospects: Uncertain.

President Donald Trump is scrambling to find a new chief of staff after his first choice to replace John Kelly bailed at the last minute and several other potential successors signaled they weren’t interested in the job.

Back to square one, Trump is mulling over a list of at least four potential candidates after Nick Ayers, Vice President Mike Pence’s chief of staff, took himself out of the running Sunday and decided that he would instead be leaving the White House. The announcement surprised even senior staffers who believed that Ayers’ ascension was a done deal.

Trump is now soliciting input on a list of candidates that is said to include Office of Management and Budget Director Mick Mulvaney, Rep. Mark Meadows, R-N.C., the chairman of the conservative House Freedom Caucus, and former New Jersey Gov. Chris Christie. And allies are pitching Trump on even more contenders.

But as quickly as names were being floated, candidates appeared to be pulling themselves from consideration, underscoring the challenges of working for a mercurial president who has acknowledged that he likes to surround himself with chaos and despises any suggestion he’s being managed.

“In the best of times, it is relentless,” said Chris Whipple, an expert on chiefs of staff and author of “The Gatekeepers,” a book on the subject. “It’s 24/7. It’s thankless. You get all of the blame and none of the credit for everything that happens. And that’s in the best of times. We are not in the best of times.”

Trump’s administration has set records for staff turnover, and the president has often struggled to attract experienced political professionals, a challenge that has grown more difficult with the upcoming threat of costly Democratic oversight investigations and an uncertain political environment.

Those who take high-level positions in the White House at this time open themselves up to potential legal exposure and pricey lawyer bills, said David B. Cohen, a political science professor at The University of Akron who co-wrote a book on chiefs of staff.

After reports surfaced Monday that he was unwilling to take the job, Meadows told Politico Playbook: “Serving as Chief of Staff would be an incredible honor. The President has a long list of qualified candidates and I know he’ll make the best selection for his administration and for the country.”

Meanwhile, U.S. Trade Representative Robert Lighthizer, a potential contender, said he was “entirely focused” on his current position. A person familiar with Treasury Secretary Steven Mnuchin’s thinking but not authorized to speak publicly made clear he, too, is happy in his current post.

While some of the reactions may be strategic posturing, there is also ample reason for any aspiring chief of staff to give pause to the notion of taking the job.

Trump has already burned through two chiefs of staff — a former chairman of the Republican National Committee and a retired Marine four-star general — subjecting them to regular humiliation and ridicule.

Former RNC Chairman Reince Priebus’s departure from the White House was unceremoniously announced by tweet. Nearly 18 months later, Trump made a surprise announcement of Kellyi’s firing.