Nowhere did Donald Trump’s candidacy inspire more trepidation or alarm than in the national security community, inhabited by many Republicans who vehemently denounced their party’s nominee as dangerously unfit to be commander in chief.

Now, as President-elect Trump begins assembling his government, scores of former senior national security officials, foreign policy specialists and career civil servants are wrestling with a dilemma: refuse government service or join the administration of the 45th president?

Whether these seasoned experts step forward to help – and whether Trump accepts them into his administration – will send a powerful signal about the new president’s intentions and ability to broaden his sphere of influencers beyond the loyalists who helped steer him to an improbable triumph in the election.

“I think it’s time for the intelligence guys to be professional and to suck it up,” said Charles Allen, who served nearly five decades in the CIA and is the unofficial dean of former intelligence community officials. “We work for the president and the Congress, and that’s all we do. We’re capable, and we have to do our job.”

While most pronounced in the national security realm, this dynamic is evident throughout Trump’s transition, which is tasked with filling about 4,100 federal jobs. Washington’s officialdom is waiting with nervous anticipation for Trump’s first appointments, especially those in the West Wing who would serve as the president’s gatekeepers.

Steve Bannon, campaign CEO for President-elect Donald Trump, leaves Trump Tower, Friday, Nov. 11, 2016, in New York. (AP Photo/ Evan Vucci)

Steve Bannon, campaign CEO for President-elect Donald Trump, is among those mentioned as a possibility for chief of staff. Associated Press/Evan Vucci

Does the president-elect install as White House chief of staff a broadly acceptable insider such as Republican National Committee Chairman Reince Priebus, who was recommended by House Speaker Paul Ryan (Wisconsin)? Or does he choose an antagonistic ideologue – perhaps Stephen Bannon, the Trump campaign chief executive who assailed the congressional leadership as chairman of Breitbart News?

Does he tap a sober-minded consensus choice such as Sen. Bob Corker (Tennessee) as secretary of state or a combustible Trump confidant such as former New York mayor Rudolph Giuliani or former House speaker Newt Gingrich, who are both said to be eyeing the diplomatic post? Does Trump appoint industry lobbyists and forsake his pledge to “drain the swamp” of special interests?

“Personnel is policy,” said Scott Reed, a Washington establishment fixture and the U.S. Chamber of Commerce’s top political strategist. “We’re going to be watching those first couple of appointments. It will set the tone on what kind of relationship the president-elect will have with the town.”

Trump campaign manager Kellyanne Conway said Saturday that a chief of staff announcement was “imminent,” telling reporters that Priebus was interested in the job and is one of several candidates Trump is considering.

So far, Trump has sent mixed signals. He selected Vice President-elect Mike Pence, who is regarded as an advocate of inclusion and a bridge to the Washington establishment and conservative think tanks, to lead the transition. He has populated his transition teams with experienced hands for areas including national security, intelligence and military.

“You don’t want to get in an echo chamber, where you only have ‘yes’ people and you don’t have any contrary thinking,” said former Republican congressman Benjamin Quayle.

Trump’s advisers said the president-elect is mindful of the importance of cultivating strong relationships with the Republican-led Senate and House to pass his agenda, including a tax overhaul and a sweeping infrastructure program.

To that end, he tapped Rick Dearborn, a former chief of staff to Sen. Jeff Sessions, R-Alabama, who is well known to lawmakers, as transition director. And Eric Ueland, a veteran Senate staffer who runs the Senate Budget Committee, has been mentioned as a likely pick to head Trump’s Office of Management and Budget.

There is talk that Trump is open to tapping a Democrat to fill at least one Cabinet position – perhaps as secretary of transportation, a nonideological post for which President Barack Obama chose Republican Ray LaHood and George W. Bush chose Democrat Norman Mineta.

Congressional Republicans, meanwhile, seem to be swooning at the unexpected opportunity to govern, though they could easily become alienated.

“I’ve been on the phone with giddy Republicans for about 48 hours now,” Rep. Tom Cole, R-Oklahoma, said. “Everybody assumed we’d come back and be the firewall against a President Hillary Clinton, and now we see the opportunity to be the point of the spear.”

Some of the Republican national security figures who signed a public letter condemning Trump during the campaign said they would never serve in his administration, and they could be blacklisted anyway. But even they have been counseling others that serving might be the right thing to do for the country.

As the seriousness of governing subsumes the vitriol of the campaign, a dozen national security experts interviewed said they believed experienced people will resume their roles as apolitical professionals and be willing to join the administration.

“I know many of those people, and some would be sufficiently patriotic to think it’s their duty,” said Jeffrey Smith, former CIA general counsel and head of Arnold & Porter’s national security law practice. “It’s just too important.”

Eliot Cohen, who served as counselor to former secretary of state Condoleezza Rice, was a driving force behind an open letter last spring, eventually signed by 122 Republican national security leaders who opposed Trump’s candidacy and pledged not to serve in a Trump administration.