“You need to have your team on the field when the clock starts,” said Max Stier, who heads the Partnership for Public Service, a Washington non-profit that focuses on good-government practices. “This is not simply about achieving the policy promises; it’s also about keeping us safe. Transitions are the point of maximum vulnerability for our nation.”

The effort is almost always well underway before a new president is elected, given the complexity and critical nature of the job, even as candidates know the work will be in vain if they are not chosen by the voters. Legislation passed in 2010, and updated in 2015, formalised much of the process for the transition from George W. Bush to Obama after the 2008 election, considered one of the smoothest in history. Trump and Hillary Clinton formed transition teams months ago that began working with the White House on first steps toward a potential hand-off.

“One of the biggest dangers is that people will underestimate the scope,” said former Utah Governor Mike Leavitt, who ran Mitt Romney’s transition team in 2012.

That may have happened in Trump’s case. Following Trump’s meeting on Thursday at the White House with the president, several Obama officials privately noted the extent to which Trump and his staff seemed unprepared to discuss basic aspects of staffing a new administration and daunted by the extent of the challenges ahead. A follow-up meeting between Trump aides and White House transition officials scheduled for Friday was cancelled, a senior Obama aide said.

To be sure, some of the observations made by White House officials could be coloured by partisan differences or concern that Trump appears set to dismantle Obama’s legacy achievements. Many had counted on a smoother transition to a Clinton administration in which top personnel would likely include former co-workers.

Trump’s decision to elevate Pence to run his transition team was one of several announced on Friday.

Pence has proved a loyal second to Trump, backing him when other establishment Republicans were critical and finding ways to explain some of his more controversial statements in public. A former member of the House, Pence also has close ties to House speaker Paul Ryan, R-Wis., and other top Republicans on Capitol Hill.

Christie’s departure came after the recent convictions of two former top aides for creating a traffic jam leading to the George Washington Bridge to punish a mayor who would not endorse him to be re-elected New Jersey governor.

“The mission of our team will be clear: put together the most highly qualified group of successful leaders who will be able to implement our change agenda in Washington,” Trump said. “Together, we will begin the urgent task of rebuilding this nation.”

Christie was retained as a vice chair of the team, along with several of Trump’s most visible campaign advisers: Dr. Ben Carson, a former Republican primary rival; former House speaker Newt Gingrich; retired Lt. Gen. Michael Flynn; former New York Mayor Rudy Giuliani and Senator Jeff Sessions, R-Ala.

Sessions, who may be the most hardline member of the Senate on immigration, has long been among Trump’s most influential advisers. Stephen Miller, a former top aide to Sessions, has been Trump’s top policy adviser and will take a similar role in the transition team. Rick Dearborn, Sessions’ chief of staff, was named as the executive director for the transition team.

Trump’s children and son-in-law, Jared Kushner, who guided him throughout the campaign, appear to have retained their influence in an official capacity. Kushner’s presence at the White House on Thursday drew notice from Obama’s staff when he asked, as they toured the West Wing, how many of the individuals there would remain into the next administration. Nearly all will depart along with the president.