do so

[Flyby]

Let's remember that it was a man from this state who first carried the banner of the Republican Party to the White House, a party founded on the values of self-reliance and individual liberty and national unity.

Those are values that we all share. And while the Democratic Party has won a great victory tonight, we do so with a measure of humility and determination to heal the divides that have held back our progress.


i don't understant exactly the meaning of the sentence in bold.

[calinative]

"We do so" refers to the act of "[winning] a great victory tonight."