Defense attorneys routinely have a choice in strategies. They can argue, “My client didn’t do x,” or they can make the case, “Maybe my client did x, but it shouldn’t matter.”

When it comes to the Trump-Russia scandal, the president’s allies have long struggled with this dynamic, to the point that they routinely end up making both arguments. For example, many on the right used to say Donald Trump and his campaign didn’t collude with Russia during its attack on the United States’ election, though some ended up arguing that collusion is permissible, so even if the Republican is guilty, we should all just look the other way.

Similarly, as the president faces allegations that he obstructed justice, the usual line from the right has been that he’s innocent. Now, however, Trump World is shifting its posture, suggesting that even if the president did obstruct justice, it shouldn’t matter.

John Dowd, who’s helping lead Trump’s legal defense, got into a little trouble over the weekend with a tweet he claims to have written for his client, but Dowd went much further in an interview with Axios.

John Dowd, President Trump’s outside lawyer, outlined to me a new and highly controversial defense/theory in the Russia probe: A president cannot be guilty of obstruction of justice. The “President cannot obstruct justice because he is the chief law enforcement officer under [the Constitution’s Article II] and has every right to express his view of any case,” Dowd claims.

On a related note, Trump tweeted this morning that Alan Dershowitz’s segment on Fox News this morning was “a must watch.” And what exactly did Dershowitz have to say? “You cannot charge a president with obstruction of justice for exercising his constitutional power,” he argued.

We are, in other words, entering a new phase of the debate. As the obstruction allegations against the president becomes more obvious, Trump’s allies are laying the groundwork for the idea that he shouldn’t, and can’t, face such a charge.

The trouble, of course, is that reality keeps getting in the way. In 1974, for example, the House Judiciary Committee wrote articles of impeachment against Richard Nixon, and the first article was on obstruction of justice. Two decades later, the House actually did impeach Bill Clinton on two counts – one of which was obstruction of justice.

If only they’d realized at the time that a president “cannot obstruct justice,” they could have saved a lot of effort.

Nixon famously told David Frost, “When the president does it, that means that it is not illegal,” but he said this in 1977 – years after he was forced to resign in disgrace.

He and his team didn’t try to make this case while Nixon was still in the White House.