Aaron Sorkin wrote an emotional and outraged letter to his teenage daughter Roxy and his wife Julia Sorkin on Wednesday, following Donald Trump‘s presidential win.

In the letter published on Vanity Fair, which he addressed to the “Sorkin Girls,” The West Wing creator expressed how he felt powerless as he watched Trump defeat Hillary Clinton on Tuesday, and how his daughter’s tears pushed him to take action.

“Well the world changed late last night in a way I couldn’t protect us from,” he began. “That’s a terrible feeling for a father. I won’t sugarcoat it—this is truly horrible.”

He went on to call the president-elect a “thoroughly incompetent pig with dangerous ideas, a serious psychiatric disorder, no knowledge of the world and no curiosity to learn has.”

Sorkin, 55, also called out “white nationalists, sexists, racists, and buffoons,” who celebrated Trump’s victory. “The Klan won last night,” he wrote.

“We’ve embarrassed ourselves in front of our children and the world,” he continued.

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The Oscar-winning scribe called on readers to “get out of bed” and take action: “We’ll f—— fight. (Roxy, there’s a time for this kind of language and it’s now.) We’re not powerless and we’re not voiceless,” he wrote. “We get involved. We do what we can to fight injustice anywhere we see it—whether it’s writing a check or rolling up our sleeves. Our family is fairly insulated from the effects of a Trump presidency so we fight for the families that aren’t.”

“America didn’t stop being America last night and we didn’t stop being Americans and here’s the thing about Americans: Our darkest days have always—always—been followed by our finest hours,” he continued.

Sorkin ended the letter with a promise to his daughter that “the battle isn’t over.”

“Your tears last night woke me up, and I’ll never go to sleep on you again,” he concluded.