The campaign against Sanders originated with hybrid PAC Democratic Majority for Israel, a pro-Israel moderate group, that spent over $1.4 million against Sanders. The group spent over $800,000 running ads against the frontrunning Democratic presidential candidate in Iowa and it's spending $600,000 in Nevada, according to recent filings with the Federal Election Commission. 

Most of the PAC's contributors have a clear history of giving money to candidates on both sides of the aisle. Its biggest donor is Stacy Schusterman, CEO of Samson Resources, an oil and gas company, who donated $1 million to the group in 2019. Schusterman has a long history of donating to Democratic candidates, except in 2016 when she contributed almost $130,000 to 25 Republican lawmakers including $2,700 to House Speaker Paul Ryan (R-Wis.).