The new platform softened language on abortion, excised old language referring obliquely to gay conversion therapy and culled a section about reducing a national debt that Mr. Trump had increased by nearly $8 trillion during his term in office.

Mr. Trump made clear to his team that he wanted the 2024 platform to be his and his alone. He wanted it to be much shorter and simpler — and, in some cases, vaguer. He was especially focused on the language about abortion, which he recognized was a potentially potent issue against him in a general election. He wanted nothing in the platform that would give Democrats an opening to attack him, and he made clear to aides that he was perfectly fine with bucking social conservatives, for whom he had delivered a tremendous victory by reshaping the Supreme Court with a conservative supermajority.

Mr. Trump also stressed that he did not want to define marriage as between one man and one woman. Instead, the document contains a vague statement open to interpretation: “Republicans will promote a Culture that values the Sanctity of Marriage.”

One person involved in the process recalled Mr. Trump saying privately: “Sanctity of marriage. Don’t define it.”