The Balfour Declaration has a lot more importance in hindsight than it really had at the time Balfour wrote it. In 1917, Britain was only just embarking on its period of greatest success in the Middle Eastern theater of World War I, when it captured Baghdad and used the Arab revolt that it had fomented the year before to dislodge the Ottomans from the Sinai and from Palestine. The Ottomans still controlled most of Palestine until around Christmas, so Balfour’s legal authority to parcel it out to the Jewish people, the Scottish people, the People Who Need People, or any other people was by no means apparent on November 2. Even after it gained control of Palestine, there’s obviously a strong moral argument to be made that Britain didn’t have the right to promise it to anybody other than the people who already lived there. But whatever its scope at the time, the Balfour Declaration became a much bigger deal as the war drew to a close, when it became a key component of Britain’s plans for the post-Ottoman Middle East.