So this is something I've been pondering a lot lately. John Balliol, Lord of Galloway, otherwise known as John I of Scotland and Toom Tabbard, came to the throne in 1292, after the great interregnum, which came about after Margaret the Maid's death, and the great cause etc. However, he had three older brothers, Hugh de Balliol, married to Agnes de Valence daughter of William de Valence, Alan de Balliol who was unmarried and Alexander de Balliol who was married to Eleanor de Genoure.
With a butterfly net in place to allow for the deaths of Alexander III, his sons Alexander and David, as well as Margaret Maid of Norway, what would change if one of John's older brothers survived past 1271, and was alive when the Maid of Norway died? Hugh is married to a cousin of King Edward I, would he be favoured for the crown? Could he, or one of his brothers win over the Bruces through offer of a marriage?
If they can, what does this change in Scotland in regards to the great cause, and the war for independence which did boil down to a succession and civil war?