Former U.S. President Donald Trump is facing fierce backlash for questioning the race of U.S. election rival Kamala Harris, but to those acquainted with the Republican's long history of inflammatory language and behavior around the issue, the smear was nothing new.

Trump's political career was forged in the cauldron of the 2010s "birther" conspiracy theory that sought to delegitimize then-President Barack Obama — who had a Kenyan father — by falsely claiming that he was born abroad.

Those who say Trump is racist point to dozens of other controversies the property tycoon has stoked, from being sued in the 1970s for discrimination against Black tenants to his notorious pandering to white supremacist marchers in 2017.