Within a foreign policy otherwise characterized by its haphazardness, the Trump administration has pursued one issue with single-minded intentionality: the Israeli-Palestinian conflict.

President Trump’s actions have consistently expressed a particularly American notion of being “pro-Israel.” But it is one rooted less in the conflict itself than in the United States’ own culture wars.

Bitter debates over terrorism and tolerance, polarized along demographic and partisan lines, have primed a faction of Americans to express their identity in part through solidarity with Israelis and opposition to Palestinians.

Politicians have long catered to this view, but Mr. Trump is first to make it official policy. Recognizing Jerusalem as Israel’s capital and threatening to close the Palestine Liberation Organization office in Washington, though never quite explained in foreign policy terms, resonate domestically.