WILMINGTON, Del. — President-elect Joe Biden announced a diverse set of nominees for top diplomatic and foreign policy posts Monday — including the first Latino and first immigrant as homeland security secretary and the first woman as director of national intelligence — as he sought to convey momentum and inevitability in building his administration.

Biden’s choices, including John F. Kerry in a new climate ambassador post, reflected his comfort with international affairs and an intent to signal the international community that a transfer of power is moving forward, even as President Trump refuses to accept his loss at the ballot box.

Antony Blinken, whom Biden has selected as secretary of state; Alejandro Mayorkas, the Cuban-born homeland security secretary-designate; and Avril Haines, tapped as director of national intelligence, all have lengthy experience at the agencies they will now lead.

President-elect Joe Biden announced Avril D. Haines as his pick for director of national intelligence on Nov. 24. (The Washington Post)

Separately, Biden is expected soon to name former Federal Reserve chair Janet L. Yellen to be his treasury secretary, according to three people in close contact with aides to Biden. If confirmed, she would be the first woman to hold that position, which was established by George Washington. Biden last week said that he would choose a treasury secretary “acceptable to all elements” of the Democratic Party.

The team announced Monday suggests that Biden has decided for now to avoid choices that would trigger heated political fights. Republican senators had signaled they would strongly oppose former national security adviser Susan E. Rice as secretary of state, for example, and Sen. Elizabeth Warren (D-Mass.), a favorite of liberals for treasury secretary, would have faced forceful resistance.

In contrast, the individuals Biden named Monday have longtime relationships with many Republicans. As a group, they inject a new diversity into the foreign policy leadership and signal that Biden intends to show the world a different face after the Trump years.

The selections seek to tell allies that the United States is back as an international partner, even as Trump takes actions such as adding sanctions on Iran during his final stretch in office, and they also seek to provide reassurance to the country’s demoralized diplomatic corps.

“They are experienced and crisis-tested,” Biden said in a statement introducing the slate. “They will keep us safe and secure. And they are leaders who look like America and reflect my core belief that America is back and that we lead not just by the example of our power, but by the power of our example.”

The president-elect plans to formally introduce the officials Tuesday at an event at the Queen, a Wilmington theater that was the venue for a number of Biden’s campaign events and has become a provisional headquarters as he prepares to take power in January.

Unlike Trump, who favored outsiders, or President Barack Obama, who often turned to up-and-coming political stars, Biden’s nominations so far are heavy on technocrats known more for competence than sparkle. Many had been rumored for weeks to be taking on big roles in the new administration.

“It’s kind of a bread-and-butter approach to governing,” said Leon Panetta, the former defense secretary and CIA director. “You’re not going for the headline, you’re going for people who you know can do the job and people you can work with.”

Other high-profile choices announced Monday were Jake Sullivan, a Biden adviser who will become national security adviser, and Linda Thomas-Greenfield, a longtime diplomat tapped to represent the United States at the United Nations.

In contrast to such figures, Trump’s first secretary of state was Rex Tillerson, a corporate executive with no government experience, and his first national security adviser was Michael Flynn, a fiery retired general who led “Lock her up” chants against Hillary Clinton at the Republican National Convention.

“It’s the difference between a president who basically rolled the dice on appointees because he had no experience in government, had few friends, and kind of operated by gut instinct and a president who knows the people he’s appointing and has had experience with them,” Panetta said.

The highest-level pick is Blinken, who has deep ties to Biden, serving as staff director at the Senate Foreign Relations Committee when Biden chaired the committee before becoming vice president. Blinken was then national security adviser in Biden’s vice-presidential office and also worked as deputy secretary of state, helping craft the Obama administration’s Syria policy.

Despite their closeness, Blinken famously broke with Biden to support military action in Libya, and he also advocated for American action in Syria. But in his emphasis on international cooperation and help for refugees, he is aligned with Biden in shifting sharply away from the Trump worldview.

Kerry, who will take on a climate portfolio, is another longtime Biden ally. Kerry acted as a surrogate for Biden during the primary, crisscrossing snowy Iowa to stump for the candidate even when he was low in the polls.

Kerry’s climate position will include a seat on the National Security Council, putting him in the room with key decision-makers amid foreign policy deliberations. It’s a signal that Biden intends to elevate climate change as an issue after an administration that played it down and even ridiculed it.

Washington Gov. Jay Inslee, a Democrat who is outspoken on the need to fight climate change, called Kerry an “excellent choice” via Twitter. “President-Elect
@JoeBiden has again demonstrated his deep commitment to follow science to save our planet and create millions of jobs,” Inslee wrote.

Biden has faced considerable pressure to appoint people with diverse backgrounds to positions of power, and he promised to do so throughout his campaign. Among his more resonant moves Monday was selecting Mayorkas to lead the Department of Homeland Security — making him, if confirmed, the first immigrant and first Latino to head an agency that oversees border control and immigration laws.

The agency became a flash point during a Trump administration inhospitable to people seeking refuge in the United States, including a policy that separated thousands of families. Years later, 545 children remain in U.S. care because the government has been unable to locate their parents, according to a recent report.

Mayorkas, who is Cuban-born, nodded to the historic significance of his nomination Monday.

“When I was very young, the United States provided my family and me a place of refuge,” he wrote on Twitter. “I have been nominated to be the DHS Secretary and oversee the protection of all Americans and those who flee persecution in search of a better life for themselves and their loved ones.”

Mayorkas was also an architect of Obama’s program to protect undocumented immigrants brought to the United States as children, a signature initiative that Trump has sought to dismantle.

The elevation of Haines to director of national intelligence will make her the first woman in that post, coordinating the country’s sprawling intelligence agencies — including the CIA, which also is headed by a woman for the first time in its history, Gina Haspel.

Trump has been at war with his own intelligence officials for much of his presidency, challenging their conclusions and becoming frustrated when they have not supported his conspiracy theories. Biden said Monday that under Haines the intelligence community “will be supported, trusted, and empowered to protect our national security, without being undermined or politicized.”

In choosing Thomas-Greenfield as ambassador to the U.N., Biden tapped an African American woman to represent the country before the international body. And he elevated the role to Cabinet level, a move that increases its status and suggests that he expects Thomas-Greenfield to have a role in internal deliberations.

Sullivan worked for Hillary Clinton when she was secretary of state before a stint on the foreign policy team in the Obama White House. He was a senior policy adviser to Clinton during her 2016 presidential campaign, and was widely expected to be her national security adviser had she won.

When Trump prevailed, Sullivan moved to New Hampshire and has been teaching, including as a senior fellow at the University of New Hampshire’s Carsey School of Public Policy. But during the general election, Sullivan was frequently spotted traveling with Biden and made a mark in domestic policy by playing a key role shaping Biden’s “Build Back Better” economic plan.

“I will do everything in my power to keep our country safe,” Sullivan said after his selection was announced.

Biden’s announcements came as Trump’s efforts to hang on to the presidency looked ever more precarious Monday.

Michigan’s Board of Canvassers voted to certify the state’s election results. A General Services Administration official issued a finding that the transition can begin. And four more Republican senators, Rob Portman of Ohio, Shelley Moore Capito of West Virginia, Lamar Alexander of Tennessee and Bill Cassidy of Louisiana said they had seen nothing to cast doubt on Biden’s win.

The choices Biden announced Monday, beyond including several longtime allies, all worked together in the Obama administration.

“The most striking thing about this group of national security advisers is how well they know each other,” said retired Adm. James Stavridis, the former supreme allied commander at NATO. “They are smart, collegial, seek no drama, and are deeply loyal to each other and their boss. It is a stark contrast with the previous administration, to say the least.”