President Donald Trump. Brendan Smialowski | AFP | Getty Images

President Donald Trump's rescinding of a White House invitation to the Golden State Warriors opened a new fissure in the cultural wars on Saturday, touching off a war of words with between the president and a growing number of professional athletes. Trump waded into a simmering debate on sports and free speech after he appeared to withdraw an invitation for the Warriors to visit the White House, and said National Football League (NFL) owners should fire players who openly protest by taking a knee on the field. Trump's remarks stirred an already thorny national conversation about the dividing lines between politics, sports and race relations, with a number of sports figures using their celebrity to advance social justice causes. At a rally in Alabama on Friday, Trump sparked a firestorm on social media by suggesting NFL players who kneel during the national anthem should be fired by owners, and in doing so used salty language.

Green with teammates Stephen Curry and Klay Thompson Ezra Shaw | Getty Images

'You're fired!'

Eric Reid #35 and Colin Kaepernick #7 of the San Francisco 49ers kneel on the sideline during the anthem Michael Zagaris | San Francisco 49ers | Getty Images