The theological dispute was inseparable from a political one. The Remonstrant position had powerful backers in the Dutch Republic's civil government, chief among them the Land's Advocate of Holland, Johan van Oldenbarnevelt, who favored toleration and resisted a national synod, while Prince Maurice of Orange, the Republic's stadtholder and military leader, sided with the Contra-Remonstrant party and moved against Oldenbarnevelt's faction in 1618. Oldenbarnevelt was arrested that August, tried on charges of treason arising from the same conflict, and executed in May 1619, within days of the Synod's own closing sessions, though the two proceedings were formally separate.
Once the Synod ruled, some two hundred Remonstrant ministers were deposed from their pulpits across the Republic, and a number, including Episcopius, went into exile; a toleration decree restored their legal standing only decades later, and a small Remonstrant Brotherhood continues in the Netherlands today. The Canons of Dort took their place alongside the Belgic Confession and the Heidelberg Catechism as the Three Forms of Unity subscribed by the Dutch Reformed Church, and the Synod's five heads of doctrine spread through Presbyterian and Reformed churches well beyond the Netherlands, later summarized under the mnemonic TULIP, a teaching device that postdates the Synod by centuries rather than a term used at Dort itself.
Maurice's purge reached beyond the church itself: in the months around the Synod, town councils and civic militias across Holland sympathetic to Oldenbarnevelt were replaced with men loyal to the Contra-Remonstrant and stadtholder's party, reinforcing the political and theological verdicts, though the Synod itself passed no sentence on him.