Her unexpected victory will probably lead Democrats to put more emphasis on the race to try to snatch a Republican seat. The winner of the Democratic primary was Diane Mitsch Bush, a former state House member who lost to Mr. Tipton in 2018.
Democrats immediately went on the attack against Ms. Boebert on Tuesday night for her refusal to disavow the QAnon conspiracy theory movement, which holds that “deep state” traitors are plotting against Mr. Trump.
Appearing on a radio program last month, she said of QAnon: “I hope that this is real, because it only means America is getting stronger and better, and people are returning to conservative values and that’s what I am for.”
“If this is real,” she added, “then it could be really great for our country.”
This month, Republican leaders condemned offensive statements about Black people, Jews and Muslims made on social media by another Republican candidate who had promoted QAnon, Marjorie Taylor Greene, who finished first in a primary for a Georgia congressional seat.
“Washington Republicans should immediately disavow Lauren Boebert and her extremist, dangerous conspiracy theories,” Representative Cheri Bustos of Illinois, the chairwoman of Democratic Congressional Campaign Committee, said in a statement issued on Tuesday night. She said Democrats were “well positioned to compete and win this seat.”