The American Israel Public Affairs Committee (AIPAC) has suffered a major electoral defeat after Dr Abdul El-Sayed won Michigan’s Democratic Senate primary, crushing pro-Israel congresswoman Haley Stevens despite an unprecedented spending campaign on her behalf.

AIPAC’s super political action committee, the United Democracy Project, spent more than $30 million promoting Stevens and attacking El-Sayed, according to Federal Election Commission filings analysed by the New York Times. NBC News projected El-Sayed as the winner on Wednesday, dealing a major blow to the pro-Israel lobby’s efforts to determine the outcome of one of the most closely watched Democratic contests in the country.

El-Sayed campaigned against US military assistance to Israel and repeatedly highlighted AIPAC’s intervention in the race. Stevens, by contrast, received the backing of AIPAC and the Democratic Party establishment.

The result is seen as providing some of the clearest evidence yet that association with Israel and its powerful lobby groups is becoming a political liability among Democratic voters as opposition grows to Israel’s genocide in Gaza and the unconditional support it receives from Washington.

A New York Times investigation published before the primary result was announced revealed the scale of AIPAC’s transformation from a traditional lobbying organisation into one of the largest spenders in US elections.