Washington: President-elect Donald Trump’s transition staff issued a blanket edict requiring politically appointed ambassadors to leave their overseas posts by inauguration day, according to several American diplomats familiar with the plan, breaking with decades of precedent by declining to provide even the briefest of grace periods.

The mandate — issued “without exceptions,” according to a terse State Department cable sent on December 23, according to diplomats who saw it — threatens to leave the United States without Senate-confirmed envoys for months in critical nations like Germany, Canada and Britain. In the past, administrations of both parties have often granted extensions on a case-by-case basis to allow a handful of ambassadors — particularly those with school-age children — to remain in place for weeks or months.

Trump, by contrast, has taken a hard line against leaving any of President Barack Obama’s political appointees in place as he prepares to take office on January 20 with a mission of dismantling many of his predecessor’s signature foreign and domestic policy achievements. “Political” ambassadors, many of them major donors, who are nominated by virtue of close ties with the president almost always leave at the end of his term; ambassadors who are career diplomats often remain in their posts.

A senior Trump transition official said there was no ill will in the move, describing it as a simple matter of ensuring that Obama’s overseas appointees leave the government on schedule, just as thousands of political aides at the White House and in federal agencies must do. The official, who spoke on the condition of anonymity about internal deliberations, said the ambassadors should not be surprised about being held to a hard end date.

The directive has nonetheless upended the personal lives of many ambassadors, who are scrambling to secure living arrangements and acquire visas allowing them to remain in the countries they have been serving in so that their children can remain in school, the diplomats said. They spoke on the condition of anonymity because they were not authorised to comment publicly on the matter.

In Costa Rica, Ambassador Stafford Fitzgerald Haney is hunting for a house or an apartment as his family — which includes four school-age children and his wife, who has been battling breast cancer — struggles to figure out how to avoid a move back to the United States with five months left in the school year, according to the diplomats.

In the Czech Republic, the sources said, Ambassador Andrew H. Schapiro is seeking housing in Prague as well as lobbying his children’s Chicago-based school to break with policy and accept them back midyear. In Brussels and Geneva, Denise Bauer, the US ambassador to Belgium, and Pamela Hamamoto, the permanent representative to the United Nations, are both trying to find a way to keep their daughters from having to move just months before their high school graduation.

Ronald E. Neumann, the president of the American Academy of Diplomacy, a Washington-based non-profit association for former ambassadors and senior diplomats, said it was reasonable to expect ambassadors to return at the end of a term, given that they are direct representatives of the president with broad grants of authority. But he could not recall an occasion in which such a strict timeline had been applied.

“When you have people out there whose only reason for being an ambassador is their political connection to the outgoing president of a different party, it’s pretty logical to say they should leave,” said Neumann, a career Foreign Service officer who held ambassadorships in Algeria, Bahrain and Afghanistan. “But I don’t recollect there was ever a guillotine in January where it was just, ‘Everybody out of the pool immediately.’”

W. Robert Pearson, a former ambassador to Turkey and a scholar at the Middle East Institute in Washington, said the rule was “quite extraordinary,” adding that it could undermine American interests and signal a hasty change in direction that exacerbates jitters among allies about their relationships with the new administration.

With the world already primed to be worrying about such an abrupt change, “this is just a very concrete signal that it is going to happen,” Pearson said.

At a White House farewell reception that Obama held on Wednesday night for non-career ambassadors, many of them commiserated over the issue, attendees said, comparing notes about how to handle the situation.

Some expressed dismay that Trump, whose wife, Melania, has chosen to stay in New York to avoid moving the couple’s 10-year-old son, Barron, to a new school midyear, would not ensure that such allowances be made for US ambassadors.

They are weighing a direct appeal to Rex W. Tillerson, Trump’s nominee for secretary of state, or other top transition officials, to reconsider the policy.

Derek Shearer, a professor of diplomacy at Occidental College who is a former US ambassador to Finland, said it was difficult to see a rationale for the decision. “It feels like there’s an element just of spite and payback in it,” he said. “I don’t see a higher policy motive.”

The State Department informed all politically appointed ambassadors in a letter the day after the election that they were to submit letters of resignation effective January 20. It instructed those who wanted to seek extensions to submit formal requests explaining their justifications.

Incoming presidents of both parties have often made exceptions to allow ambassadors to wrap up personal affairs and important diplomatic business while their successors were in the confirmation process, which can take months. Bill Clinton, George W. Bush and Obama all granted extensions for a few politically appointed ambassadors.

Former secretary of state Colin L. Powell offered particularly wide latitude to ambassadors facing family issues, said Marc Grossman, a longtime diplomat and former top State Department official who is vice-chairman of the Cohen Group, a Washington consultancy.

“This was something that was important to secretary Powell because of his own experience living and serving all over the world, so when people asked him, ‘Could I stay another couple of weeks, couple of months; my kids are finishing school,’ he was very accommodating,” Grossman said, adding that his flexibility was an “exception” to the general practice. “He was trying to, I think, send a message that family was important.”