Still, Clinton's campaign announced early Wednesday that it would not concede.

But in a tweet to supporters, the former secretary of state seemed resigned to what had to be a heartbreaking upset after working for the former first lady — who had worked for years to become the first female president in the nation's 240-year history.

"Whatever happens tonight, thank you for everything," she wrote.

Republicans retain control of the House: NBC News projections

GOP KEEPS SENATE CONTROL AS DEMOCRATS FALL SHORT