Last week the Senate voted to advance a resolution ending U.S. support for Saudi Arabia’s military campaign in Yemen. Secretary of State Mike Pompeo warned against the action, saying the U.S. ought not rebuke the Saudi government because doing so would threaten our alliance and empower Iran. But the vote wasn’t even close.

Sixty-three senators felt we couldn’t remain silent while America’s interests and values are at stake. Regardless of whether this resolution passes, it is important for Congress to signal that there is no...