Just before noon, Donald Trump will stand in front of the U.S. Capitol, place his hand on Abraham Lincoln's Bible and take the oath of office as the next president of the United States.
And the world will hold its breath.
Will Trump move ahead with his original call to temporarily bar Muslims from coming to the U.S., or stick with the revision for "extreme vetting" of potential immigrants? Will he debut a plan to provide health insurance to all Americans, or side with Republicans in Congress who have less lofty ambitions to replace President Barack Obama's health care law? Will he enter a new arms race with Russia, or trade sanctions relief for a deal cutting both nations' stockpile of nuclear weapons?
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Based on all that Trump said during his rule-breaking campaign for president, and the promises he and his nascent team of advisers made during the transition that followed, it's impossible to say. Trump has cast the opaqueness of his intentions as an asset, and his advisers have chided reporters at times for taking everything their boss says "so literally."
Former House Speaker Newt Gingrich said he knows what Trump will do Friday: give his inaugural address. But even he, a Trump ally and informal adviser, has no idea the new president will do next.
"He's not a traditional politician. He's not going to be a traditional politician," Gingrich told cheering New York Republicans arriving in Washington on Thursday for the inauguration. "None of us who elected him want him to be a traditional politician."
Despite that Election Day success, Trump enters the White House as the least popular president in four decades, according to a number of surveys. A Pew Research Center poll released on the eve of his inauguration found that 86 percent of Americans believe the country is more politically divided than in the past, the highest number since the question was first asked in 2004.
Even Trump's inauguration festivities have become controversial, upending a long tradition of both parties celebrating the peaceful transition of power. Nearly 70 House Democrats plan to boycott the ceremony. Tens of thousands will protest on the National Mall the day after his inauguration. The Girl Scouts have come under fire for marching in the inaugural parade, an event the group has participated in for more than a century.
Part of this unease undoubtedly stems from the uncertainty about what exactly comes next.
Trump's team have set forth few specific details of his top policy priorities — health care reform, infrastructure legislation and overhauling the tax code among them. His incoming administration has not specified whether Trump will fulfill a campaign promise to take 18 major executive actions on his first day in office. It's not yet clear if the U.S. will accept an invitation to attend Monday's Russian-supported Syria peace talks in Kazakhstan.
While Republicans are generally energized by Trump's win, some are also frustrated by the outstanding questions about his key proposals. "We'll see what he does," said Massachusetts GOP chairwoman Kirsten Hughes.
When Trump recently said he would craft a health care plan that provides "insurance for everybody" — a repudiation of years of GOP opposition to expanding government's role in the health care system — he rattled Republicans on Capitol Hill. Vice President Mike Pence backed away from the idea of universal coverage four days later, further adding to the confusion.
"It's possible the information is conflicting, it's possible we're just not used to hearing the new president communicate yet," Missouri Republican Sen. Roy Blunt told CNN this week.
It's not even clear who Trump will have at his side in the first days of his time in office.
When President Barack Obama took office in 2009, the Senate confirmed seven Cabinet members on Inauguration Day. Republicans and Democrats are still negotiating over Trump's picks, and it looks unlikely more than four will make it through on Friday.
According to the Partnership for Public Service, a nonprofit that's advised Trump's transition, his team has nominated 29 of the 690 federal government positions that require Senate confirmation. Aides announced Thursday that Trump had asked 50 senior Obama administration appointees to remain in their posts after his inauguration to ensure continuity in government.
Yet for all the disquiet that surrounds his arrival in Washington, Trump appears unfazed by it all. At the first stop on his inauguration weekend agenda, Trump had a simple message Thursday for a lunch-time gathering of supporters, future staffers and appointees at his Washington hotel.
"I just want to let the world know we're doing very well together," he said.