It's impossible for Trump to 'obstruct justice,' his lawyer says

Trump's lawyer John Dowd outlines new defense in Russia probe.

A sitting president cannot obstruct justice, Trump lawyer John Dowd told ABC News in a statement today, citing Article II of the Constitution.

The "president cannot obstruct justice because he is the chief law enforcement officer under Art II and has every right to express his view of any case," Dowd added.

Trump's tweet sparked renewed talk of possible evidence of obstruction of justice because his tweet seemed to acknowledge that he knew Flynn had lied to FBI investigators before firing him in February.

Dowd confirmed to ABC News he drafted Trump's social media post and sent it to Trump's social media director, Dan Scavino.

The special counsel's office announced Friday that Flynn pleaded guilty to one count of lying to the FBI about his negotiations with Kislyak before Trump assumed office.