A progressive Jewish political action committee with ties to the son of Democratic Party mega-donor George Soros is intervening in Senate races for the first time, endorsing Rep. Tammy Duckworth of Illinois and former Sen. Russ Feingold of Wisconsin. The endorsements from Bend the Arc Jewish Action PAC will involve fundraising support from the group, which makes direct payments to candidates running for office. It will also marshal what are known as “conduit” payments, linking its network of donors to the group's favored candidates. “As American Jews, we’re disturbed by the dark turn American political discourse has taken in recent...