Haley Stevens

Rarely is the top issue in a high-profile election how, exactly, the contest has been funded.

But that has been the case in the Democratic primary race for Senate in Michigan, which has inflamed so many of the party’s explosive political debates.

Representative Haley Stevens, the moderate establishment-backed candidate, benefited from about $62 million in advertising spending from half a dozen outside groups. Over half of that sum came from the super PAC arm of the American Israel Public Affairs Committee, the country’s most influential pro-Israel group.

That spending gave her and her allies about a 9-to-1 spending advantage over her progressive rival, Dr. Abdul El-Sayed, and his allies, according to data from the media tracking firm AdImpact. Two main ads from the group targeted Dr. El-Sayed over his past criticisms of women like Michelle Obama and Gov. Gretchen Whitmer of Michigan and featured positive comments about Ms. Stevens from former President Barack Obama as part of her attempt to appeal to Black voters.