In an essay published this summer outlining portions of her economic program, the senator and presidential candidate Elizabeth Warren wrote that “far too often, the private-equity firms are like vampires—bleeding the company dry and walking away enriched even as the company succumbs.” Elyse Wien, although admittedly sympathetic to Warren’s politics, detects a sinister note:

Warren shows no evidence of being . . . an anti-Semite, but she does seem to be a party to the left’s growing reliance on outrage in their search for a bogeyman in the financial elite—a search that invariably appeals to conspiracy theorists and anti-Semites. . . . [I]t’s necessary to step back and examine the roots of the left’s contempt for finance when that contempt extends beyond the specifics of policy to the nature of finance itself. The idea that finance is “vampiric,” that it feeds off the honest productivity of hard workers to extract unmerited earnings, is a sentiment that has direct roots in a long history of anti-Semitism.

The idea that money derived from finance is parasitic because it is not from “productive” labor was developed by medieval Christian natural-law theology but has even older origins in the work of Aristotle. . . . While the political radicals of the 19th century did not explicitly extol natural-law theology, . . . they nevertheless betrayed the influence [of medieval economic thinking] in their emotionally charged distinction between productive and parasitic labor, and the particular vitriol they showed toward both finance and Jews.

For [19th-century] anti-Semites of both the left and right, . . . the political emancipation of Jews was, [to paraphrase Karl Marx], the result of turning the world “Jewish”; the Jews’ freedom was purchased through the immiseration of others. The template created by Marx and other 19th-century thinkers who connected their opposition to finance and capitalism with the purported “Jewishness” of those practices would proliferate in subsequent decades, taking root in cultures outside Europe, as financial capitalism also spread across the globe.

William Jennings Bryan’s 1897 “Cross of Gold” speech is a classic of 19th-century American populism, yet the historian Richard Hofstadter notes . . . that perhaps nothing did more to reinvigorate American anti-Semitism than the frequent allegations that the “Shylocks” and “Rothschilds” controlled the banks that controlled the farms.

If there is to be peace, Palestinians will have to unlearn the hatred of Israel they have imbibed during nearly two decades of Hamas rule. This will be a difficult task, but Cole Aronson argues, drawing on the experiences of World War II, that Israel has already gotten off to a strong start:

The population’s compliance can . . . be won by a new regime that satisfies its immediate material needs, even if that new regime is sponsored by a government until recently at war with the population’s former regime. Axis civilians were made needy through bombing. Peaceful compliance with the Allies became a good alternative to supporting violent resistance to the Allies.

Israel’s current campaign makes a moderate Gaza more likely, not less. Destroying Hamas not only deprives Islamists of the ability to rule—it proves the futility of armed resistance to Israel, a condition for peace. The destruction of buildings not only deprives Hamas of its hideouts. It also gives ordinary Palestinians strong reasons to shun groups planning to replicate Hamas’s behavior.