The third person on tonight’s debate stage might be the most important. So who is Kristen Welker?

NBC News’ Kristen Welker will moderate tonight’s debate. Her name has been in the news a lot the past few days, mostly because President Donald Trump keeps running her down, calling her “terrible” and “totally partisan.” But she’s a well-respected journalist, even earning praise from Trump adviser Jason Miller, who called her “very fair.”

She is especially well respected inside NBC News. When she was named a moderator, NBC News President Noah Oppenheim told his staff, “The selection of Kristen as a moderator is a testament to her talent, skill, work ethic and tenacity. As she demonstrated during the November presidential debate, Kristen will ask the tough and necessary questions on behalf of American voters. Anyone who knows Kristen knows this — there is preparing, and then there is the way Kristen prepares. As Andrea (Mitchell) noted on air today, ‘No one works harder … she does more homework than anyone I have ever known.’”