The continued discord between the outgoing Obama administration and the incoming Trump administration is setting the stage for one of the more contentious presidential transitions in recent memory, and may present the country with dire national security threats as a result.

The two teams have clashed on matters of policy, foreign relations and hypothetical election results, culminating with a Dec. 28 tweet from President-elect Donald Trump that the transition would not be a smooth handover of power.

Despite efforts to walk back those sentiments following a phone conversation between Trump and President Barack Obama that same day, there is speculation that after witnessing one of the better transitions in modern presidential history in 2009, the current inauguration may be one of the most contentious on record.

"It’s really hard to change direction once things start rocketing down the road they are on now," said Don Kettl, professor and former dean of the School of Public Policy at the University of Maryland. "It’s clear that the two teams don’t like each other much. It’s also clear that within the Trump transition team that teamwork is at a premium.

"There are a lot of dissenting views with people fighting for oxygen and fighting for access. So both the incoming Trump team’s ability to speak as a team and the ability of that team to interact with outgoing Obama people, that seems likely to get worse for a while."

But as exhaustive research on presidential transitions by both the Partnership for Public Service and the National Academy of Public Administration have shown, there’s little time for communication breakdowns between administrations.

Starting more than a year out from the upcoming inauguration, both think tanks produced a series of research papers and roundtables with former administration officials to game-plan what a smooth transition of power would look like, in part because of the vulnerability such a transition creates for the country.

"Both the incoming and outgoing administrations must steadfastly commit to making the transfer of power not only peaceful but also effective," Max Stier, president and CEO of the Partnership for Public Service, told Federal Times in an email.

"This is a time of high vulnerability for our nation and in a post-9/11 world, the national security imperative requires the utmost cooperation and effort on both sides of the transfer to strengthen and uphold this cornerstone to our democracy," Stier said.

Speaking at the opening of the Partnership’s Center for Presidential Transition on Jan. 20, 2016, former George W. Bush Chief of Staff Josh Bolten detailed how officials from the outgoing administration worked hand in hand with new Obama appointees to effectively navigate a credible terror threat while the inauguration was unfolding.

"The night before the inauguration, the Department of Homeland Security picked up credible threat information about an intended attack on the inauguration festivities themselves," he said.

"[We were] trying to figure out how to best do the handoff and especially how to prepare the incoming team for a situation in which they might face a national security crisis and an attack on the homeland not just in Year One, in Hour One."

With the legal authority of Bush’s Department of Homeland Security set to expire at noon, a potential attack could have put the new Obama administration into a crisis situation before much of the Cabinet had even moved into its offices.

By 10 a.m., Bolten had brought incoming Chief of Staff Rahm Emanuel to a joint briefing, and both Homeland Security teams had gathered together in a command center to assess the nature of the threat.

"We had arranged with the Obama administration to sit side by side the day before and the day of the transition, even though the Constitution was clear on who actually makes the call to try and assist each other," Bolten said. "The threat turned out not to be real, but the intelligence was pretty serious.

"The point of the story is that there was no template for this. We were making it up as we went along."

While contentious presidential transitions have happened before — including a truncated timetable following Bush’s 2000 win — there hasn’t been one since the Sept. 11, 2001, attacks, creating a new paradigm that emphasizes the importance of cooperation.

"The world is just much more interconnected than it’s ever been," Kettl said. "That means everything from perhaps less obvious having to do with the financial system to the obvious questions about both homeland security and international security. The risks and the costs of missteps are far higher than they have ever been before."