Religious groups rarely vote as a fully unified bloc. For instance, in the South Carolina Republican primary, white evangelical Christian voters were split among those who voted for Donald Trump (34%), Ted Cruz (26%), Marco Rubio (21%) and others, according to exit polls.

But looking at the religious makeup of individual states, and at each party’s potential voters within a particular state, can still help in understanding the electoral landscape. Indeed, as voters for one or both parties in 12 states prepare to cast ballots or caucus on March 1 – Super Tuesday – we looked at data from Pew Research Center’s 2014 Religious Landscape Study to help shed light on who might vote and their potential motivations.

Republicans in general tend to place a higher level of importance on religion than do Democrats, and this holds true across the Super Tuesday states. Two-thirds of Republicans and those who lean toward the GOP in these states (66%) say religion is very important to them, compared with 53% of Democrats. For Democrats and Democratic leaners, religion’s importance varies widely among states – from Vermont, where 21% of Democrats say religion is very important to them, to Alabama, where 84% of Democrats say the same.

Overall, nearly half of all people in the 12 Super Tuesday states who identify as or lean toward the Republican Party (47%) are evangelical Protestants.

Members of evangelical Protestant churches make up huge shares of Republicans in most Super Tuesday states, including majorities in Tennessee (67%), Alabama (63%), Arkansas (61%) and Georgia (57%). Evangelicals also make up 56% of Republicans in Oklahoma and nearly half (46%) in Texas, which will be the biggest prize of the day, with 155 GOP delegates at stake.

Massachusetts, one of the five states outside the South to vote Tuesday, is the biggest exception to this trend; only 10% of Massachusetts Republicans are evangelicals, while fully half (50%) are Catholics. But even though 79% of Massachusetts Republicans identify with a religious group, only a third (33%) say religion is very important in their lives. In several other Super Tuesday states – Alabama, Arkansas, Georgia, Oklahoma, Tennessee, Texas and Virginia – two-thirds or more of Republicans say religion is very important to them.

Among Democrats, people with no religious affiliation are the largest group in three of the 11 states that will vote Tuesday (Alaska Republicans will caucus Tuesday, but Democrats in Alaska will do so on March 26). This includes Massachusetts (where religious “nones” make up 37% of Democrats), Colorado (38%) and Vermont, where fully half of Democrats are religiously unaffiliated.

Overall, religious “nones” (atheists, agnostics and those who say their religion is “nothing in particular”) make up a quarter of Democrats (25%) in the 11 Super Tuesday states, compared with about half as many Republicans (13%) in the 12 GOP states.

Members of historically black Protestant churches also are a key Democratic constituency, especially in Alabama (39%) and Georgia (32%). While 15% of all Democrats in the party’s 11 Super Tuesday states are members of historically black Protestant denominations, this group makes up only 2% of Republicans in the 12 GOP states.

While evangelical Protestants typically are associated with the Republican Party – and are far more likely to identify with the GOP nationally – they still make up a substantial share of Democratic voters in many states. Evangelicals are the single biggest group among Democrats in Tennessee (39%), and they make up 20% of all Democrats in the 11 states that will vote Tuesday.

In Massachusetts (27%) and Texas (26%), about a quarter of Democrats are Catholics; in Texas, the overwhelming majority of Catholic Democrats (79%) are Hispanic. Meanwhile, in Minnesota, about a third of Democrats (34%) identify with mainline Protestant churches.

Correction: In a previous version of the chart “Religious affiliation of Republicans in Super Tuesday states,” several bars in the “unaffiliated” column appeared larger than intended; the numbers shown were correct.