In one of the country’s closest House races, Adam Frisch, a Democrat challenging Representative Lauren Boebert ColoradoA far-right gunslinger, known for her provocations on Capitol Hill and her extreme right views, endorsed Friday as Ms. Boebert looked increasingly likely to win another term. The race was not called by the Associated Press.

Mr. FrischMs. Boebert was 35. was seen as a heavy favorite Enter the race Colorado’s Republican-leaning Third Congressional District.

As of Thursday evening, according to The A.P., Ms. Boebert led by a mere 0.16 percentage points — or 551 votes of nearly 327,000 counted to date. According to The A.P., almost all votes have been counted. According to The A.P., the margin is eligible for an automatic recount under state law. This would delay an official race call.

Mr. Frisch had sought to cast Ms. Boebert as a flamethrower in an increasingly polarized Congress, who he said was more focused on placating the Republican Party’s far-right Trump wing than reducing inflation and adding jobs.

A television commercial portraying him as not a typical Democrat — it showed footage of Mr. Frisch hunting with a shotgun — he said that he would not vote for Representative Nancy Pelosi for House He said that he was a supporter of border security.

However, Ms. Boebert’s inability to name the district and the composition of the voters made it difficult for Mr. Frisch to defeat her. Her fiery actions have attracted national attention.

Ms. Boebert, who is also a Republican in her first term, brought a non-stop, no-holds-barred style of politics to the party, along with Representative Marjorie Taylor Greene from Georgia. HouseThis is a result of a social media echo chamber that supports former President Donald J. Trump. This has made Ms. Boebert a target for platforms such as Twitter, who temporarily suspended her account following the falsehood that the 2020 elections were rigged.