WASHINGTON — When progressive House Democrats fought a vote to pass aid for Israel’s Iron Dome defense shield, the outrage among both mainstream Democrats and Republicans boiled over. Florida Democratic Rep. Ted Deutch asserted that the opposition permitted “the dismantling of the one Jewish state in the world.” The National Republican Senatorial Committee labeled the progressives as “anti-Israel radicals.” In the end, just 4% of House Democrats — eight in total, along with one Republican — Kentucky Rep. Thomas Massie — voted against the $1 billion defense appropriation in September. But in the two months since then, the Senate’s taken...