President Trump reportedly derided the late Sen. John McCain's book sales at a private lunch for television anchors on Tuesday, hours before he was expected to call for optimism and unity in his State of the Union speech. 

According to a report from the New York Times, Trump targeted McCain as he bad-mouthed several Democrats. 

"By the way, he wrote a book and the book bombed," Trump reportedly said, presumably referring to McCain's memoir, "The Restless Wave."

The late senator's daughter, Meghan McCain, fired back in a tweet Tuesday night, calling Trump's comment "pathetic."

"The president’s obsession with my father 6 months after his death is pathetic and telling - even at a time when he should be focusing on his message to the American public and the state of our union - the greatness of my father’s life and legacy haunts you," she wrote. 

Arizona's former senator died in August after stopping treatment for brain cancer.

More on Sen. McCain's life and death here: