In May 1977, three years after he resigned the presidency, Richard Nixon made a stunning declaration. The president, he told British journalist David Frost, in a series of historic interviews, is not bound by the same laws that apply to ordinary citizens. “When the president does it, that means that it is not illegal,” he explained. Congress, which filed articles of impeachment for obstruction of justice in the Watergate affair, obviously disagreed. Yet 40 years later, Donald Trump’s legal team has revived Nixon’s reasoning. As special counsel Robert Mueller closes in on what appears to be an obstruction case against the president, Trump’s attorneys are publicly laying the groundwork to argue that he is immune to any charges that could precipitate impeachment.

The extraordinary defense being outlined appears to anticipate two interconnected claims: that he was aware of or abetted a quid pro quo between his campaign and the Russian government, and that he subsequently worked to sabotage federal investigations into alleged collusion. The linkage is critical: as members of Washington’s white-collar defense bar told me after Trump fired James Comey, to prove obstruction Mueller must also prove corrupt intent. That doesn’t necessarily mean that he must uncover an underlying crime. But it does mean that Trump or his associates must have been attempting to conceal something.

From the outside, this pattern of deception seems obvious. Members of Trump’s campaign have lied repeatedly about their contacts with Kremlin officials. As we now know, multiple Trump associates—including Trump’s eldest son—communicated with Russian intermediaries seeking to coordinate efforts to defeat Clinton and, later, to normalize diplomatic relations in exchange. After the election, Michael Flynn called Russian ambassador Sergey Kislyak to encourage Vladimir Putin not to respond to the sanctions that President Barack Obama had just imposed on Russia in retaliation for meddling in the race—a move that Trump transition officials feared would undermine their own foreign-policy goals. “If there is a tit-for-tat escalation Trump will have difficulty improving relations with Russia, which has just thrown U.S.A. election to him,” one Trump transition official, K. T. McFarland, wrote in an e-mail obtained by The New York Times. When Putin held his fire, anticipating friendlier treatment by the incoming administration, Trump was ecstatic. “Great move on delay (by V. Putin),” the president-elect tweeted in December. “I always knew he was very smart!”

While the White House has said that there was no collusion (a claim Trump reiterated to reporters this weekend, after Flynn pleaded guilty to lying to the F.B.I. about his contacts with Kislyak), the president’s lawyers have moved to arguing that it would not be illegal. “For something to be a crime, there has to be a statute that you claim is being violated,” White House lawyer Jay Sekulow told Jeffrey Toobin of The New Yorker. “There is not a statute that refers to criminal collusion. There is no crime of collusion.”

On Monday, John Dowd, another Trump lawyer, went further. “[The] president cannot obstruct justice because he is the chief law enforcement officer,” he told Mike Allen of Axios. Over the weekend, Trump had appeared to admit to obstructing justice when he tweeted that he knew Flynn lied to the F.B.I. when he fired him, raising questions about his subsequent decision to dismiss Comey. Dowd, who later claimed, without evidence, that he had written the controversial tweet, dismissed the media furor as “ignorant and arrogant.”