In late 2010, Tom Nides sat down for lunch with the throwback diplomat Richard Holbrooke on the second floor of Kinkead's, a legendary seafood restaurant near the State Department's headquarters in the Foggy Bottom section of Washington.

Nides had just been nominated to succeed Jack Lew as deputy secretary of state, and Holbrooke, who was serving as the US special representative for Afghanistan and Pakistan, wanted to give Nides the lay of the land. Nides thought that meant a status update on the region.

But Holbrooke, who paid attention as meticulously to the ups and downs of the Washington elite as he did to the twists and turns of international deal-making, intended to detail the department's power structure. As they ate, Holbrooke explained that Nides must acquaint himself with a singular force in Secretary Hillary Clinton's inner circle.

"Let me tell you, the only person and the one person you need to get to know, who is loved by everyone in the institution and gets things done, is Jake Sullivan," Holbrooke said.

Now, it's the House Select Committee on Benghazi that will be getting to know the blue-eyed, sandy-haired Minnesotan at the center of Clinton's foreign policy operation. He is scheduled to appear Friday for a closed-door session before the panel, which is investigating the 2012 terrorist attacks that killed four Americans in eastern LIbya and Clinton's email.

It's a high-profile moment for the 38-year-old Sullivan, who quietly catapulted through the ranks of the Democratic foreign policy establishment, working as a top policy hand at State and as national security adviser for Vice President Joe Biden between stints on Clinton's presidential campaigns.

But he is accustomed to handling delicate tasks. Sullivan was tasked with running the Clinton campaign's foreign policy, an area in which the candidate's hawkish instincts diverge from those of war-wary progressives.

For liberals hoping Clinton will undergo a left-oriented metamorphosis on foreign policy to match the economic and social policy transformations that have her sounding more and more like an Elizabeth Warren acolyte, Sullivan's selection will be a disappointment. He won't drag Clinton to the left — or anywhere else.

"He's in line with her," said Ben Rhodes, a deputy national security adviser to President Barack Obama. "On the spectrum of people in our administration, he tended to favor more assertive US engagement on issues" and "responses that would incorporate some military element." That included early advocacy for arming Syrian rebels when he worked for Clinton at State and the Ukrainian military when he was Biden's national security adviser.

"Reject cynicism. Reject certitude. And don't be a jerk."

Like Clinton, though, Sullivan is decidedly dedicated to the proposition that no ideology or solution fits every situation.

"Reject cynicism. Reject certitude. And don't be a jerk," he advised the University of Minnesota's public policy graduates in a 2013 address. "Now, when I say 'reject certitude,' I don't mean your core principles. You can and must be certain about those ... But in public policy, principles simply point the way — they do not provide specific answers about what to do in specific circumstances."

He and Clinton both subscribe to the non-philosophical school of so-called "smart power." A concept developed by Harvard professor and former Defense Department official Joseph Nye, smart power encompasses the use of both hard power favored by hawks (military threat, force, and sanctions) and the soft-power levers favored by foreign policy doves (foreign aid, forging cultural and economic bonds, and negotiation).

"Jake was not the most experienced diplomat at the State Department I could have chosen..."

In the confines of the national political debate, hard power and soft power are black-and-white choices. In the smart power construct, they are not at odds; they are complementary. And while Sullivan is more given to the use of force than many in the Obama administration, he's also shown a willingness to engage diplomatically with some of the toughest customers in the world.

He was one of a handful of Obama White House aides looped into the effort to reestablish ties US ties to Cuba. Before that, Clinton dispatched him to Oman in 2012 to begin negotiations with Iran over a possible deal to roll back economic sanctions on Tehran in exchange for restrictions on the country's nuclear enrichment program.

"Jake was not the most experienced diplomat at the State Department I could have chosen, but he was discreet and had my absolute confidence," Clinton wrote in her memoir Hard Choices. "His presence would send a powerful message that I was personally invested in this process."

"Ugh!"

As important as sharing Clinton's worldview, Sullivan's developed a role in her orbit as a solicitor, and distiller, of the best arguments on all sides of a debate, and as someone who is widely trusted as an honest broker among the sometimes warring factions of Hillaryland. Former Undersecretary of State Bob Hormats, who spent eight years working at the National Security Council in the 1960s and '70s, says Sullivan's approach is reminiscent of that of Brent Scowcroft, who served Presidents Gerald Ford and George H. W. Bush as national security adviser.

"He is known to have strong views but also was good at pulling together the views of people whose opinions he trusted"

When done well, the national security adviser's job is to collect the wisdom, insights, and policy preferences of the president's war Cabinet and present them with as little prejudice as possible. Sullivan's role on the campaign, like his role at State, is similar to that. There's no learning curve. His tendencies are her tendencies. Veteran Clinton foreign policy aides say he would be on the short list for the national security adviser post if she wins the presidency.

"He is known to have strong views but also was good at pulling together the views of people whose opinions he trusted and conveying those to the secretary so she could see different perspectives," Hormats said. "In many ways I think his temperament and his interlocutor role are similar to those of Brent Scowcroft, who was extremely knowledgeable and well-respected for these traits. ... And, like Jake, he stayed out of the limelight."

When I emailed Sullivan to tell him I was working on a profile of him, he replied in four characters:

"Ready to make commitments"

Sullivan, the second of what would become a set of five kids, was born in Burlington, Vermont, a few weeks after Jimmy Carter's 1976 election, and later moved to Minnesota. Until he was well into his 30s, he had only really observed one Democrat in the presidency: Bill Clinton.

At Minneapolis Southwest High School, Sullivan was a standout on the debate and quiz bowl teams, garnering "most likely to succeed" honors. He graduated from Yale in 1998, went to Oxford on a Rhodes scholarship, and then returned to Yale for law school.

That's where he first met Harold Koh, the renowned human-rights lawyer and international law expert.

Koh, who would go on to become dean of the law school and then serve as Clinton’s top lawyer at State, recalls Sullivan volunteering to help with the legwork on an amicus brief for the Supreme Court in the landmark case Lawrence v. Texas. The case looked like it could be a watershed moment for the attainment — or rejection — of civil rights for the gay and lesbian community. Sullivan felt it was important to push that needle forward.

Yale's role brought together Sullivan's values on a domestic policy matter with his interest in international law. His desire to jump into the fray showed he was "ready to make commitments" to social justice issues, Koh said. It was also a sign that he shares Clinton's view that domestic policy is a factor that affects America's ability to lead abroad.

In the brief, Koh and colleagues argued that the Supreme Court should weigh the conclusions of foreign and international courts in determining whether a Texas statute banning same-sex sodomy violated the Constitution. The 6-3 majority opinion overturning the Texas law noted, "Other nations, too, have taken action consistent with an affirmation of the protected right of homosexual adults to engage in intimate, consensual conduct." Sullivan would go on to clerk for Supreme Court Justice Stephen Breyer, who sided with the majority in the Lawrence case.

Years later, when Koh and Sullivan worked together as top State advisers, Clinton delivered a speech in Geneva in which she equated gay rights and human rights, a formulation designed to signal that the US would judge foreign countries' human rights records in part on how they treated members of the LGBT community.

"I speak about this subject knowing that my own country's record on human rights for gay people is far from perfect," Clinton said. "So we, like all nations, have more work to do to protect human rights at home."

When Sullivan left Biden's office last year, he went back to Yale to be close to his fiancée, Maggie Goodlander, a former adviser to Senators Joe Lieberman and John McCain, who is pursuing a law degree. In New Haven, he and Koh co-taught a class on foreign policy and law, where Sullivan pushed students to deliver debate-style arguments and then critiqued them to show how they could be sharper.

Like Clinton, another Yale-trained lawyer, Sullivan simply loves assessing the arguments, Koh said.

Winning friends and influencing Obama

Sullivan prepped Clinton for her 2008 debates with Obama and other Democrats. He did such a good job that, after the primary, Obama's team borrowed him from Clinton to help the future president get ready for his face-offs with Republican nominee John McCain.

When Obama won the White House, Sullivan told friends he planned to head home to Minnesota, where he wanted to practice law and eventually run for office — possibly then–Rep. Michele Bachmann’s House seat. Clinton changed that arc by offering him a newly created job as her deputy chief of staff for policy at the State Department. He was 32 when he was sworn in.

"Jake did everything for Secretary Clinton."

He quickly accumulated influence within the department, becoming Clinton's right hand in formulating policy, conducting diplomacy, writing speeches, and, at times, dealing with the media. Colleagues say he showed a unique ability to dive into and out of issues, and to move from the crisis of the moment to long-term planning. And, of course, he had an uncanny knack for knowing what Clinton would want done.

A wee-hours reader and emailer, Sullivan developed a reputation for cutting through bureaucratic thickets to get decisions quickly on even minor items. That helped him suck up turf and authority at State, where he was eventually given additional duties as the head of the department's in-house strategic think tank, the Office of Policy Planning.

Perhaps most impressive, though, is the way he earned the trust of both Clinton and Obama’s foreign policy team at a time when the two camps were still feeling each other out. Sullivan formed a bond with two of Obama’s national security aides, Denis McDonough and Ben Rhodes, often channeling the view of the White House within the State Department.

Though he gained notoriety with conservatives for being part of the email chain on Benghazi talking points, the truth is that he was in near-constant communication with the White House on all manner of issues for four years.

For example, when Clinton accused Pakistan of harboring Osama bin Laden in 2009, Sullivan quickly reached out to see if Obama’s aides wanted her to walk it back. The answer: double down. The close contact on even minor issues reduced the real and inevitable tension between Obama and Clinton camps that had fought bitterly over the Democratic nomination and didn't always see eye to eye on foreign policy matters.

Sullivan, unlike the vast majority of Clintonworld, had formed relationships with Obama's team during the 2008 general election campaign. That's one reason he became a go-to resource for the White House. The other: he was one-stop shopping on policy, diplomacy, and communication.

"Jake did everything for Secretary Clinton," Rhodes said.

In another episode in 2009, Sullivan took up the White House's cause in pushing for the ouster of Jared Cohen, a member of the Policy Planning Office staff who asked Twitter founder Jack Dorsey to delay scheduled maintenance of the company's platform because members of the Iranian Green Movement relied on it to communicate.

Obama had just said the US wouldn’t interfere in Iran’s domestic politics, and Cohen’s intervention, which was leaked to the New York Times, made it look like the president wasn’t honoring that promise. From Sullivan's point of view, which matched that of the White House and some veteran diplomats, the story about Cohen's action could backfire on the Green Movement. The demonstrators had signaled they would lose credibility if fellow Iranians saw them as puppets of Washington.

Clinton had a different take on the matter, telling her top aides that Cohen’s effort was exactly what the US should be doing.

That episode in June 2009 was one of the rare occasions when Sullivan and Clinton diverged. He was at her elbow for nearly every stop on her marathon, four-year tour of the world. When he wasn't literally by her side, it was because he was representing her with foreign officials.

"When he shows up somewhere, they know he speaks for Hillary and he speaks to Hillary," Koh said.

"The cat's meow"

Often, a Washington staffer reflects one or two traits of his or her boss — or quickly learns to adopt them. Sullivan clearly reminds Clinton of herself: lawyerly, organized, detail-oriented, and capable of moving from issue to issue without losing his place. And, of course, his pragmatic streak on policy matches hers. He also shares a few of Bill Clinton's traits, most notably a rare likability.

"When Jake Sullivan first came to work for me, I told my husband about this incredibly bright rising star — Rhodes Scholar, Yale Law School — and my husband said, 'Well, if he ever learns to play the saxophone, watch out,'" Clinton once said, adding that when she traveled as secretary of state she talked to people all over the world who wanted to "meet a potential future president of the United States — and of course they mean Jake."

As Nides put it, "Hillary thinks he is the cat's meow."

While Sullivan has made a big name for himself in Washington over a short period of time, and is well-positioned to join a possible second Clinton administration in a powerful role, he often tells friends he wants to return home — at least for a while — and run for elective office.

That may be informed, in part, by his desire to be closer to his roots.

With one exception since 2001, Sullivan has traveled to the NCAA men's basketball Final Four city to meet up with his siblings. They show up, without tickets, and try to find their way into the arena, according to a friend. Another friend said growing up in a household full of smart kids has helped Sullivan keep an even keel in the choppy waters of Washington politics and international diplomacy.

Teammate of rivals

It was back to Minnesota that Sullivan planned to go when Clinton left the State Department in early 2013. He was finally going to set up that run for office. But he ended up staying in Washington for a job that would increase his value to Clinton as a foreign policy adviser and keep him in the middle of an issue — a nuclear deal with Iran — that presents tremendous risk to her in 2016.

Clinton had refused Obama's request to stay in her job, and the White House didn't want to lose Sullivan, too. The biggest job available was national security adviser to Biden.

Sullivan insisted that, once again, he had his heart set on going back home so he could eventually come back to Washington as an elected official in his own right.

Obama sealed the deal by telling Sullivan, among other things, that he could be far more influential as Biden's national security adviser than as a junior member of Congress, according to a person familiar with their conversation. It was a line Sullivan had heard before, from Nides and others. Obama, who served less than one term in the Senate, knew from back-benching it on Capitol Hill.

And though he was assigned to the vice president's office, Sullivan understood the role would give him access to the president's daily briefing on intelligence and put him in the Situation Room for National Security Council meetings. In those ways, it represented an ideal training ground for becoming the president's national security adviser.

White House officials say there was never any tension surrounding Sullivan's decision to work for Biden — a path Clinton encouraged him to follow — because everyone knew that if she ran for president, Sullivan would go with her. He had risen with her, and his views on US engagement with the world fit hers much better than Obama's or Biden's. Biden, for example, was against the raid that killed Osama bin Laden and striking Libya.

Sullivan participated in a series of meetings with Clinton and foreign officials in Paris and the Middle East in which the Libya coalition was stitched together. He handed her the phone when she asked Russian Foreign Minister Sergei Lavrov, from a television greenroom in Tunisia, to abstain from a Security Council vote on Libya.

From the vice president's office, he continued to be part of the US negotiating team on an Iran deal that Republicans, and some Democrats, say places too much trust in Tehran. The administration believes it is the only path to ensuring Iran is unable to develop a nuclear weapon in short order. After Sullivan left the administration last year — for the teaching post at Yale rather than a run for Congress — he continued to participate in the P5+1 talks with Iran.

"You can't be effective that way"

A few weeks after Holbrooke advised Nides to develop a relationship with Sullivan, Holbrooke's heart burst in a meeting with his deputy Frank Ruggiero, Clinton, and Sullivan at the State Department. In typically animated fashion, he had been arguing against the administration's policy on dealing with the Taliban as Obama tried to wind down the war in Afghanistan.

In Holbrooke's view, it was worth sitting down with Taliban leaders to see if a deal could be struck in which they would sever their relations with al-Qaeda and live by the new constitution of Afghanistan. The White House position was that those concessions should be pre-conditions of negotiating with the Taliban. Holbrooke thought they should be pre-conditions for a deal, but not for a meeting. On that matter, Sullivan was with the White House.

"Diplomacy deserves a chance"

As Holbrooke made his impassioned plea to Clinton, he heaved and turned red. His aorta had torn open. Sullivan and Ruggierio came to his aid and hustled him to a nearby elevator so he could be rushed to George Washington University's hospital. Holbrooke died a couple of days later.

He had once told a colleague, after finding himself talking to Sullivan when he called for Clinton, that Sullivan could someday be secretary of state.

Less than two years after Holbrooke's death, Sullivan was assigned to reach out to Iran about a possible nuclear deal, without apparent pre-condition. He continued to work on the developing deal even after he left Washington. The controversial premise on which it hinges — that the agreement can be so sound as to prevent Iran from acquiring a nuclear weapon — is politically risky for Clinton. But she endorsed it, first in a closed-door meeting with House Democrats in July and then publicly.

Like Clinton, Sullivan, for better and worse, has shown situational flexibility in his approach to foreign policy. Often, there's no perfect choice on the table. And what works for one problem may not work for another.

"The minute you start treating public policy problems like arithmetic problems, with an absolute right and an absolute wrong answer, quit," he told the Minnesota graduating class. "You can't be effective that way. In a world of imperfection, you will not find a flawless position, which means that whatever position you adopt will inevitably have weaknesses or blind spots. You should acknowledge them."