Senator Bernie Sanders, the progressive former presidential candidate who rose to prominence in part by denouncing the influence of wealthy interests in politics, has a new target in his sights: the American Israel Public Affairs Committee and its affiliated super PAC, which is spending heavily in Democratic primaries for the first time this year.After Mr. Sanders traveled last week to Pittsburgh to campaign for Summer Lee, a liberal state legislator whose House campaign was opposed by millions of dollars in such spending, he is now headed to Texas. There, he is aiming to lift up another progressive congressional candidate, Jessica Cisneros, whose left-wing challenge of a moderate incumbent has been met with significant spending from the pro-Israel super PAC.“This is a war,” Mr. Sanders said in an interview, “for the future of the Democratic Party.”AIPAC has long been a bipartisan organization, and its entry this year into direct political spending has included giving to both Democrats and Republicans. That has earned the ire of Mr. Sanders and other progressives because the group’s super PAC also ran ads attacking Ms. Lee as an insufficiently loyal Democrat.“Why would an organization go around criticizing someone like Summer Lee for not being a strong enough Democrat when they themselves have endorsed extreme right-wing Republicans?” Mr. Sanders said. “In my view, their goal is to create a two-party system, Democrats and Republicans, in which both parties are responsive to the needs of corporate America and the billionaire class.”Mr. Sanders specifically called out the committee for donating to congressional Republicans who refused to certify the 2020 election, while its super PAC, the United Democracy Project, has framed itself as a pro-democracy group.“That just exposes the hypocrisy,” Mr. Sanders said.Marshall Wittmann, a spokesman for AIPAC, said in response to Mr. Sanders, who is Jewish, that the group “will not be intimidated in our efforts to elect pro-Israel candidates — including scores of pro-Israel progressives.”“It is very revealing that some who don’t take issue with super PAC support for anti-Israel candidates get indignant when pro-Israel activists use the same tools,” Mr. Wittmann said.After the Pennsylvania and North Carolina PrimariesMay 17 was the biggest day so far in the 2022 midterm cycle.The Stakes: G.O.P. voters are showing a willingness to nominate candidates who parrot Donald J. Trump’s 2020 lies, making clear that this year’s races may affect the fate of free and fair elections in the country.Trump’s Limits: The MAGA movement is dominating Republican primaries, but Mr. Trump’s control over it may be slipping.Trump Endorsements: Most of the candidates backed by the former president have prevailed. However, there are some noteworthy losses.Up Next: Closely watched races in Georgia and Alabama on May 24 will offer a clearer picture of Mr. Trump’s influence.More Takeaways: Democratic voters are pushing for change over consensus, nominating a left-leaning political brawler for Senate in Pennsylvania. Here’s what else we’ve learned.The three candidates that Mr. Sanders has been most personally invested in backing so far have also had all super PAC support, though two were heavily outspent.Despite more than $3 million in opposition spending from pro-Israel groups, Ms. Lee is narrowly ahead in her primary against Steve Irwin, a lawyer; The Associated Press has not yet called the race.In North Carolina, Nida Allam, the Sanders-backed candidate, lost to Valerie Foushee, a state legislator, in an open congressional race. Ms. Foushee’s campaign was supported by nearly $3.5 million in spending from two pro-Israel groups and a super PAC linked to a cryptocurrency billionaire. Super PAC spending for Ms. Allam was $370,000.Maya Handa, Ms. Allam’s campaign manager, said Mr. Sanders’s megaphone — he did robocalls, sent a fund-raising email to his giant list and held a virtual event — brought invaluable attention to the outside money flooding in the race.The message broke through to some voters. In Hillsborough, Elese Stutts, 44, a bookseller, had been planning to vote for Ms. Foushee. However, on Election Day, Ms. Stutts said, she was turned off after learning about the origin of the super PAC money that had helped Ms. Foushee’s campaign.Ms. Foushee ultimately won the Democratic primary for a district that includes several major universities, including Duke and the University of North Carolina at Chapel Hill, and where Mr. Sanders registered 83 percent favorability among Democratic primary voters in the Allam campaign’s polling.Mr. Sanders has sparred with pro-Israel groups over the years, including during his 2020 presidential run, when a group called the Democratic Majority for Israel PAC spent money to attack him when he emerged as a front-runner early in the primary season.And when one of Mr. Sanders’s national co-chairs, Nina Turner, ran for Congress in a special election in 2021 and again in 2022, that group and the AIPAC-aligned super PAC both spent heavily to defeat her.Understand the 2022 Midterm ElectionsCard 1 of 6Why are these midterms so important? More