“The mainline”: America’s older churches.

Mainline is a bit of Christianese in the United States. The adjective refers to the Protestant churches in the United States who were around since the 1700s—since before our constitutional freedom of religion made it possible for all sorts of new churches to crop up, and add to the thousands of Protestant denominations.

Some of these churches, like the Baptists, Congregationalists, and Unitarians, got their start here. Others, like the Episcopal, Presbyterian, and Methodist churches, got their start in England and Scotland—but when the colonies declared independence from the UK in 1776, the churches reorganized their leadership to become distinct from their UK governing bodies.

So being “mainline” or a “mainliner” doesn’t refer to a belief system. They’re not mainliners by philosophy: Other than Jesus’s teachings and Protestant traditions, they don’t necessarily have a lot in common. (In the case of Unitarians, the rest of us figure they’re heretic.) They’re mainline because they’re older. They have a longer history. They were here when the United States began.

But for many politically and theologically conservative Christians, “mainliner” has become their shorthand for a politically progressive or theologically liberal Christian. Because a number of mainline churches are liberal in their beliefs. Not all of ’em, but just enough for “mainliner” to pick up another definition.

So when you hear Christians refer to certain churches as “mainline churches,” sometimes you gotta ask them: Do you mean old, or liberal? (Maybe both.)