Separated by the entire North American continent and half the Pacific Ocean, the incoming and outgoing presidents are trading barbs – both veiled and overt – from their respective holiday vacations, souring a once a collegial public relationship. Marked by insults on Twitter, perceived public slights and foreign policy disputes, the ties between President-elect Donald Trump and President Barack Obama have significantly frayed less than a month before Trump is sworn into office. Both sides say the actual mechanics of transferring power from one administration to another are proceeding smoothly. The President-elect said he spoke with Obama Wednesday in what he termed a “nice conversation.” And Trump’s spokesman said Wednesday he expected more conversations between the two men before Inauguration Day on January 20. Trump, however, has become more open in his criticism of the President since he won last month, arguing on Twitter that Obama misjudged the election and lost badly. He scaled up his disparagement on Wednesday, writing that “inflammatory” statements from Obama were hampering a smooth transition. Obama has also offered criticism of his successor, albeit more tacitly. During a historic speech Tuesday in Pearl Harbor alongside Japanese Prime Minister Shinzo Abe, Obama cautioned against tribalism and isolationism – warnings that, during the campaign, he used to argue against Trump’s candidacy. The latest back-and-forth comes after two weeks of open sparring between the White House and Trump’s transition team over Russia and Israel. Once contained to sniping between aides, the squabbles have escalated to Obama and Trump themselves. The result is an openly antagonistic relationship between the commander in chief and the man who’s about to replace him, a dynamic that both men explicitly worked to avoid in the days immediately following the election. Initial cordiality In public, both Obama and Trump had been careful to avoid direct personal criticism of one another in the weeks following November’s vote. White House officials said Obama’s instructions were to maintain a professional and helpful tone, hoping to provide Americans reassurance in the peaceful hand-off of power. Trump, too, offered conciliatory signals. He was effusive during his first meeting with Obama in the Oval Office, the bitterness of the campaign and any remnants of his “birther” conspiracy vanished. Later, Trump revealed he was speaking regularly with Obama, describing a “warm” relationship fostering discussions about potential Cabinet picks. Obama had hoped his counsel might convince Trump to maintain some of his administration’s work on climate change, health care and foreign policy. He regarded Trump as a largely non-ideological pragmatist who might be open to his guidance. A more combative tone eventually emerged, though Obama and Trump both sought to keep tensions at a minimum. Even Trump, known for his bombast, attempted to model the Obamas’ “when they go low, we go high” mantra, praising the President at rallies even as his crowd booed. The President-elect sought to brush off a tiff with First Lady Michelle Obama, saying she misspoke when she told Oprah Winfrey that “we are feeling what not having hope feels like.” Obama, too, attempted to ratchet down tensions surrounding Trump’s dismissal of US intelligence blaming Russia for a cyberintrusion in the election. After a week in which his press secretary hammered Trump’s operation for questioning the finding, Obama sought to cool the temperature, saying in his year-end news conference the matter shouldn’t be caught up in politics. Barbs begin But disagreements over Israel this week and a suggestion from Obama he could have won in a contest with Trump seem to have ended the politesse. “I could’ve mobilized a majority of the American people to rally behind” a hope-and-change message, Obama told his senior adviser David Axelrod for The Axe Files podcast interview released Monday. It wasn’t long before Trump began tweeting in an progressively more irksome tone: “President Obama said that he thinks he would have won against me. He should say that but I say NO WAY! - jobs leaving, ISIS, OCare, etc,” he wrote on Monday. A day later: “President Obama campaigned hard (and personally) in the very important swing states, and lost. The voters wanted to MAKE AMERICA GREAT AGAIN!” After Obama’s Tuesday appearance in Hawaii warning against “the tug of tribalism” and “the urge to demonize those who are different,” Trump’s language on Wednesday morning was more direct. “Doing my best to disregard the many inflammatory President O statements and roadblocks,” he wrote. “Thought it was going to be a smooth transition - NOT!” The White House declined to comment on Trump’s accusation. Trump’s incoming White House press secretary, Sean Spicer, downplayed any trouble. “The current President and his team have been very helpful and generous with their time,” he said. But he didn’t temper the acrimonious messages directed toward Obama and the transition. “With respect to the tweets, they speak for themselves, I think very clearly,” Spicer said.