By Katie Bo Williams and Jordan Fabian - 12-24-16 16:04 PM EST
Donald Trump challenged longstanding U.S. policy in key areas of the world during his presidential campaign.
Now he must choose the corps of ambassadors who will serve on the front lines as he seeks to change American diplomacy.
Trump has already selected envoys to China, Israel and the United Nations.
Here are five other top picks for the president-elect.
The most closely watched pick left for Trump might be his pick as U.S. ambassador to Russia, a country accused by U.S. intelligence agencies of interfering in the presidential election, possibly to help Trump win.
Trump's relationship with Russian President Vladimir Putin is his most scrutinized, and the entire world will be looking to see if Trump names a pro-Russia figure to make good on his promise of warmer relations with the Kremlin.
The post is famously difficult - former officials note it's almost impossible to get by without speaking Russian - and usually goes to a career diplomat.
But right now, speculation is centered on a member of Congress who for three decades has bucked hard-line Republican attitudes toward Russia.
Rep. Dana Rohrabacher (R-Calif.) has declined to comment specifically on the rumors but told The Washington Post that the transition team has discussed several possibilities with him.
Rohrabacher has criticized NATO - once in Trump's crosshairs - of "vilifying" Russia.
Like Trump, he has also flatly rejected the intelligence community's assessment that hacks of the Democratic National Committee (DNC) and other political organizations were part of a high-level effort by the Kremlin to install Trump in the White House.
Some former State officials see Rohrabacher as a hard sell, suggesting that he may have difficulty getting confirmed by the Senate.
Trump's promise to build a wall on the Mexican border is perhaps the most famous, and one of the most controversial, vows of his campaign.
It will make selecting an ambassador to Mexico tricky.
Whoever Trump picks will have to wade through a thicket of thorny issues, including Trump's crude comments about Mexican immigrants, his call for a renegotiation of the North American Free Trade Agreement (NAFTA) and his demand that Mexico pay for the wall.
Career diplomats have traditionally served as the U.S. ambassador to Mexico, given the two nations' complex history. But it appears Trump is poised to make a nontraditional pick.
One leading candidate is Al Zapanta, the longtime head of the U.S.-Mexico Chamber of Commerce.
Zapanta says he has spoken to members of Trump's transition team about the role, but no decision has been made.
"It's like everything else - your name comes up, but don't count chickens until they hatch," he told The Hill.
His business and military background - he earned a Purple Heart in Vietnam - could appeal to the president-elect. He was also an early supporter of Trump's campaign and is leading a working group to present policy recommendations to him early next year.
Other names that have been mentioned are Texas billionaire Toby Neugebauer, the son of a GOP congressman; Larry Rubin, president of the American Society of Mexico and a go-between for Republicans and Mexican officials; and former Attorney General Alberto Gonzales.
Trump may turn to an establishment figure to be his ambassador to Japan, one of the nation's key military and economic allies in Asia.
Speculation has centered on former Utah Gov. Jon Huntsman Jr., who was President Obama's first ambassador to China. Trump's White House chief strategist, Steve Bannon, reportedly would like to see Huntsman in Tokyo.
Huntsman knows the region well. Besides his experience in China, he also served as ambassador to Singapore under President George H.W. Bush.
Japan has served as a crucial military outpost for the U.S. since the end of World War II, but Trump could preside over a period of significant change. The president-elect on the stump suggested that the U.S. was paying too much for the defense of Japan and might withdraw troops.
And tensions over the U.S. military presence in Okinawa have been on the rise following the May arrest of a former Marine for murdering a 20-year-old Okinawa woman.
Reports have also circulated that Trump is weighing the selection of former Mets manager Bobby Valentine to fill the post.
The post of U.S. ambassador to the United Kingdom typically goes to a political appointee or campaign donor, not a career diplomat, because the close relationship between the two nations has remained relatively stable for generations.
That could change under Trump, who backed the "Brexit" referendum.
It's possible Trump could offer to negotiate a new trade agreement with Britain as a reward for leaving the European Union. That would be a complex undertaking that would require deft diplomacy.
But Trump is expected to stick with the approach favored by past U.S. presidents and hand the post to a supporter.
Speculation has centered around New York Jets owner Woody Johnson, a deep-pocketed Republican donor and friend of Trump's.
Multiple media reports have cited Johnson as a leading contender for the role after he was spotted at Trump Tower on Dec. 5.
Bannon has also reportedly thrown his weight behind a pick for NATO: Michele Flournoy, a top Pentagon official in the Obama administration who was widely seen as likely to become secretary of Defense had Democratic nominee Hillary Clinton won the White House.
But Flournoy has already denied interest in taking a role in the Trump administration. Her think tank, Center for a New American Security, put out a Monday statement saying she was staying put.
The pick for permanent representative to NATO will take the post at a time of tense uncertainty for the organization.
Trump famously said he would not automatically rush to aid a fellow member if they were attacked - a core tenet of the alliance.
The remarks represented an unprecedented break with U.S. commitment to the alliance, predicated on deterring Russian aggression in Europe.
The new ambassador will also take the reins at a time when relations between NATO and Russia have been at a historic low - and when NATO's second-largest military, Turkey, appears to be moving closer to Moscow amid tense relations with the U.S.