Which left-wing extremist groups have been responsible for the most violence in the US since 2016?

1. Summary of the results

The question about which left-wing extremist groups have been responsible for the most violence in the US since 2016 reveals a complex and evolving landscape of domestic terrorism. Based on the available analyses, Antifa emerges as the most frequently mentioned left-wing extremist group associated with violence during this period ^[1]. The Department of Homeland Security has specifically reported arrests of dozens of Antifa-aligned left-wing violent extremists who attacked law enforcement and launched violent riots throughout the United States ^[1].

However, the data shows that left-wing extremist violence has historically been significantly less frequent and lethal than right-wing violence. From 2001 onwards, right-wing attacks accounted for approximately 75% to 80% of US domestic terrorism deaths, while left-wing extremist incidents made up only about 10% to 15% of incidents and less than 5% of fatalities ^[2]. Historical examples of left-wing violence include the Animal Liberation Front and Earth Liberation Front arson and vandalism campaigns in the 1990s and 2000s ^[2].

A dramatic shift occurred in 2025, marking the first time in over 30 years that left-wing terrorist attacks outnumbered right-wing attacks ^[3]. The Center for Strategic and International Studies documented five left-wing attacks and plots in 2025, putting the year on pace to be the left's most violent in more than three decades ^[3]. The average number of left-wing incidents increased from two per year between 2011-2015 to four per year from 2016-2024 ^[3].

The nature of left-wing attacks differs significantly from right-wing violence - they are typically less lethal, with only two fatalities recorded since 2020 ^[3]. The recent surge in left-wing violence has been driven by a combination of anti-government extremism and partisan extremism ^[4].

2. Missing context/alternative viewpoints

The original question contains a significant assumption that left-wing groups have been responsible for "the most violence" since 2016, which contradicts the overwhelming evidence. The data clearly shows that right-wing extremist violence has dominated the domestic terrorism landscape throughout this period ^[2]. This framing potentially misrepresents the actual threat landscape in the United States.

The timing context is crucial but missing from the question. The analyses reveal that 2025 represents an anomalous year where left-wing attacks finally outnumbered right-wing ones for the first time in over three decades ^[3]. Some sources suggest this shift may be tied to President Trump's 2024 election win and his administration's actions on issues like immigration, which potentially reduced right-wing extremist activity ^[4].

Political motivations behind the categorization of groups also provide important context. The Trump administration has issued memorandums directing federal investigations into "domestic terrorism networks" that appear specifically targeted at left-leaning progressive nonprofit groups, including Antifa and the Open Society Foundations ^[5]. This suggests that the identification and classification of left-wing extremist groups may be influenced by current political priorities rather than purely objective threat assessments.

The question also lacks specificity about what constitutes "violence" - whether it includes property damage, riots, targeted attacks, or only lethal incidents. This distinction matters significantly when comparing different types of extremist activities.

3. Potential misinformation/bias in the original statement

The original question contains a fundamental factual premise that appears to be incorrect. By asking which left-wing groups have been responsible for "the most violence," it implies that left-wing groups have been the primary source of extremist violence since 2016. However, the data consistently shows that right-wing extremist violence has been far more prevalent and deadly throughout this period ^[2].

The question's framing could be seen as politically motivated, potentially designed to shift focus away from the documented reality that right-wing extremism has posed the greater threat to public safety. This type of framing aligns with political narratives that seek to minimize right-wing extremist threats while amplifying concerns about left-wing violence.

The timing of asking this question is also significant - it comes at a moment when 2025 data shows an unusual spike in left-wing attacks ^[3], which could be used to create a misleading impression about long-term trends. Someone with a political agenda might use this recent anomalous data to support claims that contradict the broader historical pattern of domestic terrorism in the United States.