Presidential debate host Kristen Welker: 4 things you need to know

President Trump is already attacking Thursday's presidential debate moderator, NBC News' Kristen Welker, who has served as the company's White House correspondent since 2011.

"Kristen Welker is terrible," Trump told "Fox & Friends" on Tuesday. "She is totally partisan. Her father and mother are big supporters of Joe Biden. They're supporters of the Democrat Party."

Welker's parents have donated tens of thousands of dollars to Democrats, including nearly $20,000 to former President Barack Obama.

Welker appears to be refraining from any response to the president's remarks ahead of the final...