"Everybody knows that in 1964, a proud southern Democratic President, Lyndon Johnson, pushed hard to secure the Civil Rights Bill, with the aid of a coalition of northern Democrats and Republicans," Wilentz said. "This sent the defeated segregationist Southern Democrats (led by Strom Thurmond) fleeing into the Republican Party, where its remnants, along with a younger generation of extremist conservative white southerners, including Rand Paul, still reside."
The NRSC email came in the middle of wild day for Paul that saw him walk back his previous statements on the '64 law, including criticisms of the law's impact on private business. Walsh's email was attached to a statement from the Paul campaign that tried to stop the bleeding as the story developed.
"I wanted to make sure you saw the statement below from Dr. Rand Paul making clear that he supports the Civil Rights Act and would not support any efforts to repeal or change it," Walsh wrote. Then that he took the swipe at Democrats for attacking Paul for criticizing the law the way some of them did back in '60s.
Walsh pointed to one specific Democrat -- Sen. Robert Byrd (D-WV) as an example of the irony he was referring to. Byrd spent time as a young man as a member of the Ku Klux Klan before repudiating the group later in life.
"In fact, the sitting President pro tempore of the Senate, elected to this leadership position by his current fellow Senate Democrats, was one of the leaders of [the '64 Civil Rights Act] filibuster," Walsh wrote.
Wilentz said that any suggestion that Democrats talking about the Civil Rights act is somehow hypocritical is pretty much a complete rejection of the actual facts -- and the political landscape at the time.
"In many ways, the 1964 Act defined the modern political parties -- with the Republicans becoming the heirs to the traditions of the Confederacy and Jim Crow, and the Democrats embracing the tradition of Abraham Lincoln," he wrote.
He said that the history of the bill shows that Republicans didn't hold the high ground when it came to supporting Civil Rights.
"Brian Walsh may have forgotten that Lyndon Johnson ran for president in 1964 against a Republican nominee, Barry Goldwater, who repudiated the Civil Rights Act," Wilentz wrote.