Get breaking news alerts and special reports. The news and stories that matter, delivered weekday mornings.

This weekend brings Easter Sunday and the beginning of Passover, and Christians and Jews will be filing into houses of worship this weekend to celebrate – most certainly more than usual for what are considered important holy days for people of both religious persuasions.

The difference in the number of people in those churches and temples this weekend has a political significance. Often we talk about how different religious groups vote at election time, but the data show that the bigger divide in the electorate is around religious attendance – how often people go to a house of worship.

Let our news meet your inbox. The news and stories that matters, delivered weekday mornings. This site is protected by recaptcha

In 2012, for instance, Republican Mitt Romney won the vote coming from Protestants, capturing 57% of their vote. President Barack Obama won the vote coming from Catholics, Jews, people of other affiliations and people of no affiliation, some by large margins.

But the Obama/Romney split is even clearer when you look at it by religious attendance. There was a clear linear progression for both candidates in 2012, with Mr. Obama’s support rising as church attendance falls and the opposite true for Mr. Romney.

The church attendance differences are most stark when you look at Catholics.

Yes, Mr. Obama won the overall Catholic vote in 2012, but Mr. Romney beat the president handily among Catholics who attended church at least weekly – 57% to 42%. In fact, those figures matched exactly the margins Mr. Romney had over Mr. Obama with Protestant Christians.

But among more casual Catholics, those who attend church less than once a week, Mr. Obama defeated Mr. Romney with similar ease – 56% to 42%. (There are similar differences among protestant voters, though Mr. Romney won both regular church attendees and less-frequent churchgoers.)

The message in these numbers? There will not only be more people in the pews around this weekend in your house of worship, there will probably be a different body politic.