To start, I say 'colonies' because the following examples are not Scottish colonies as such but British colonies with large Scottish influence.
The regions of Appalachia in the USA and Antrim in Northern Ireland are some of the most religious parts of their respective countries. These are regions with heavy Scottish influence in their histories. They are also regions which allow politics and religion to link up very often, with Appalachians often voting Republican and much of Antrim voting for the DUP. In contrast however, Scotland itself is one of the most progressive countries in the UK and Europe and has exclusively voted for left wing parties since the foundation of Scotland's Devolved Government.
Why is this?
It’s very difficult not to answer this with a ‘no true Scotsman’ joke, but indeed a big factor is that the ‘Scotch-Irish’ aren’t as culturally and religiously in step with Scotland as the name would imply. The settlers in Ulster, and their ‘Scotch-Irish’ descendants in Appalachia, were dominantly from rural northern England and the Scottish borders. The settlement of Ulster was part of a James I/VI’s ultimately disastrous project to culturally unify the West European Isles particularly in regards to religion: he personally saw Catholics as “lost in superstition” and wished to “establish the true religion of Christ among men”. He also wanted to break the links between the Gaelic clans in western Scotland and the Gaels of eastern Ireland, which he believed was contributing to political unrest.
This meant that settlers had to be Protestants (preferably Anglican) and speak either Middle Scots or Early Modern English, which are two closely related Germanic languages derived from Old English.The first settlers were dominantly Scottish Presbyterians, who initially outnumbered the Anglican English settlers five to one. This influence can still be seen in Ullans, the local dialect of the Scots language. During the 1620s, the Church of Ireland, an outpost of the Church of England, was established and recognized as the state religion. By 1630, there were about 50,000 settlers in Ulster, and the Irish Gaels were unsurprisingly outraged.
In 1641, the outrage coalesced into an organized rebellion, which killed about a quarter of the settlers-- the overwhelming majority were Gaelic Irish Catholics, but there is evidence that a small number of Scottish Presbyterians ditched the settlements to fight on the Irish side. The settlers held onto the land due to a combination of local militias and an influx of armed Covenanters who came to Ireland as part of a deal with Cromwell’s government would leave the Kirk alone in exchange for Scottish military support in Ireland. (County Antrim later received an influx of Scottish Presbyterians during the “seven ill years” of famine in the 1690s).
This is where I need to pause for a side trip to cover the difference between the Presbyterian Church of Scotland and the Anglican Church of England. Christianity came to Scotland via Ireland in the 6th century CE (Ireland had converted during the 5th century). This branch of Celtic Christianity kept its own religious calendar, allowed priests to marry, relied on traveling clergy rather than regular church attendance, and did not officially recognize the authority of the Pope in Rome. It wasn’t until the early to mid-8th century that the Gaelic and Brythonic Celtic people in Scotland synced with Rome and adopted the liturgical calendar and rites of mainland Europe. The Celtic Church was regularly accused of “Judiazing” the Church due to collective interest in the Old Testament and the Jewish roots of Christianity, including an emphasis on studying scripture. When the Reformation arrived in Scotland in the 1550s, Scottish reformers such as John Knox, John Craig, and George Buchannan focused on the anti-authoritarian and social justice elements of Reformation theology; some early Scottish reformers such as John Major advocated with some success for Native American human rights under Spanish rule, and other 17th century reformers publicly condemned chattel slavery. The original organizing documents of the Church of Scotland (“the Kirk”) emphasized the autonomy of individual congregations and a democratic system of church government; it also included an ambitious plan to fund universal education and a network of services to aid the poor with assets seized from Catholic nobles. In the end, the plan went largely unfunded (Parliament didn’t want to anger the nobles), though not totally unrealized. Unsurprisingly, James I/VI, newly King of England and Supreme Guardian of the Anglican Church (see below) distrusted the Kirk, kicking off a power struggle between the Kirk and James I/VI and his successors, part of which manifested in the Covenanter movement during the War of the Three Kingdoms. The Covenanters’ goals included a theocratic government, support of monarchy, and intolerance of other religions.
In what is now England, Christianity had been introduced to the native Brythonic Celts by the Romans during the 1st century CE. After the collapse of the Roman Empire, however, the native Christians did not have any success converting the pagan Anglo-Saxons who moved in. In the 6th century, the Pope sent missionaries who successfully converted the Anglo-Saxons and connected them to the authority of Rome. This state of affairs continued until Henry VIII split with Rome and declared himself Supreme Head on Earth of the Church of England. Conflict escalated, with his daughter Mary returning England to Catholicism and violently persecuting Anglicans. At the same time, Reformed theology, particularly Calvinism, was catching on in England. A series of laws, known as the Elizabethan Settlement, was passed during Queen Elizabeth’s reign and served as a compromise; the Anglican Church retained the authority structure and rites of Catholicism, but introduced Reformed doctrine.
Back to the Ulster settlers. Religious conflict in Scotland between factions of the Kirk resulted in the most extreme Covenanter elements being killed, imprisoned, or transported; less radical Covenanters were quietly reintegrated into the mainstream Kirk during the 1680s. Many Scottish Presbyterians in Ulster returned to Scotland, especially those who were recent migrants or preferred the mainstream Kirk to the more extreme Covenanters. Despite recurrent schisms, the main Kirk returned to an agenda focused on social welfare, including opposition to slavery. In 1688, Catholic monarch James II/VII was deposed in favor of his Protestant son-in-law. Now feeling secure from the Catholic “threat”, the Ulster Anglicans turned on their remaining Presbyterian allies. Some were killed, others converted to the Church of Ireland, and others immigrated to the British colonies in North America, predominantly what is now Pennsylvania and Virginia. These ‘Scotch-Irish’ migrants, as they were called by English colonists, came from a much more conservative and extreme branch of Presbyterianism than their Scottish counterparts; they were later joined by more Ulster migrants, now coming from an even more rarified pool of people committed to (or at least very comfortable with) colonialism, monarchy, theocracy, and more extreme interpretations of Reformed theology. This community-- including the earlier Presbyterian migrants-- also retained a sense of persecution from previous generations’ collective experiences in the 1641 rebellion.
Reading/Sources