In his speech, Mr. Biden sought to confront those doubts by embracing what may become a legacy-defining moment in his presidency: the challenge of uniting the country to help people far beyond America’s borders. Mr. Biden took his case for the new spending directly to the public less than two weeks after Hamas terrorists slaughtered more than 1,400 Israelis and just two days after an explosion at a hospital in the Gaza Strip killed as many as several hundred Palestinians. Mr. Biden visited Israel in a whirlwind trip on Wednesday, and in his speech, he said flatly that the hospital...