The 'Harry Potter' author was writing in response to an article by Iain Macwhirter in which in which he claimed "every trace of ethnic nationalism was expunged from the party in the 1970s".
Rowling immediately took issue with the statement.
Macwhiter expanded upon his original point.
With Rowling questioning how this one assertion could ensure there was not "any trace" of anti-English sentiment in the party today.
The conversation provoked a spirited response.
But Rowling defended her remarks.
Rowling - born in England - often clashes on Twitter over the issue of Scotland where she currently lives.
The Labour supporter faced a torrent of abuse after the party's disastrous defeat in the General Election.