Barack Obama is president for another five weeks. Will he retaliate against Russia before he leaves? And if so, how?

Those are the most pressing questions Obama will face on Friday afternoon as he holds his final press conference of the year—and perhaps his presidency. Don’t expect him to detail precisely how the United States will respond to what the government considers solid evidence that Russia interfered in the presidential election on behalf of Donald Trump. But Obama has already hinted that a retaliation may be in the offing.

“I think there is no doubt that when any foreign government tries to impact the integrity of our elections ... we need to take action,” Obama said in an NPR interview that aired Friday morning. “And we will—at a time and place of our own choosing. Some of it may be explicit and publicized; some of it may not be.”

The reality is that Obama has precious little time left to choose for a response to Vladimir Putin, and his decision to further escalate tensions in the weeks before he leaves office threatens to unravel the surprisingly cordial and cooperative relationship he’s forged with his successor, President-elect Donald Trump.

That awkward alliance is already fraying amid reports that the CIA believes the Russians hacked Democratic email accounts with the express purpose of helping Trump defeat Hillary Clinton. Trump has disputed the claims and falsely asserted that the Obama administration kept quiet about Russian interference before the election. In a Friday tweet, he went a step further and once again brought up one of the revelations from the emails that Russian hackers purportedly stole:

Are we talking about the same cyberattack where it was revealed that head of the DNC illegally gave Hillary the questions to the debate? — Donald J. Trump (@realDonaldTrump) December 16, 2016

At a rally Thursday night in Pennsylvania, Trump called White House press secretary Josh Earnest “a foolish guy” after the spokesman reminded reporters that it was the Republican nominee who explicitly asked Russia to hack Clinton’s emails during the campaign. Obama will likely face questions Friday both about Trump’s rhetoric and whether there was more his administration could have done to prevent Putin from so brazenly meddling in the election.