In a blowout presidential election, a few large issues dominate. In a tight election, a range of smaller concerns — important to strategic constituencies in battleground states — can end up being crucial.

President Obama may have hoped for a decisive reelection victory, styled on Ronald Reagan’s in 1984. At best, he will return to the White House in the manner of George W. Bush in 2004 — after a scrambling fight across the Electoral College map. In this election, Americans are overwhelmingly focused on the economy, with cultural issues lagging in priority. But it does not follow that cultural debates are electorally unimportant. For Obama, they could matter among the wrong groups in the wrong places.

Consider the Catholic vote. In the aggregate, the category is not particularly coherent. Hispanic Catholics are more Democratic in orientation than white Catholics are. Very religious Catholics are more Republican than their less observant brethren are. A shared faith does not always mean shared political behavior. The term “Protestant” applies to African American voters and white evangelicals, to Episcopalians and Southern Baptists. Catholicism, while more institutionally united than Protestantism, has at least as much cultural, theological and political diversity.

But this does not mean a subset of Catholicism can’t be electorally important. White, non-Hispanic Catholic voters could matter greatly in some tight state contests. And Obama has done his best to alienate them.

The main offense has been the Health and Human Services Department’s mandate for contraception, sterilization and abortion-inducing drugs under Obamacare — a regulation that turns Catholic hospitals, universities and charities into instruments of a federal policy they find offensive. Between early March and mid-April — soon after the mandate battle was joined — the Pew Research Center found that Obama’s support among all Catholics fell from 53 percent to 45 percent. Among white Catholics, it dropped from 45 percent to 37 percent. These numbers have remained depressed. Obama won 54 percent of Catholic voters in 2008. A recent Gallup survey found Obama’s Catholic support at 46 percent.

Correlation is not causation. But, in this case, it doesn’t seem mere coincidence. John White, a political science professor at the Catholic University of America, finds Obama’s decline among Catholics “in large part due to the recent debate over health care and contraception.” Many Catholics have issues with their own institutions. It does not mean they want those institutions targeted by government. They are happy to criticize their own bishops — but not to hear the views of their bishops insulted by politicians.

And HHS Secretary Kathleen Sebelius is a continuing insult to the beliefs of traditional Catholics. Testifying at a recent House hearing, Sebelius admitted that she had consulted no constitutional precedents and asked for no legal advice from the Justice Department while making her decision on the contraceptive mandate. “Congressman,” she explained, “I’m not a lawyer and I don’t pretend to understand the nuances of the constitutional balancing tests.” The only thing worse than indifference to religious liberty is casual, ignorant indifference to religious liberty.

I’ve previously argued that the Obama administration, motivated by instinctual liberalism, stumbled into this conflict with Catholic leaders. It is possible, however, Obama is making the political calculation that appealing to younger, non-religious voters is worth the alienation of traditional Catholics. Yet even if this strategy makes sense nationally, it might not be wise in, say, Pennsylvania or Ohio, where the votes of white Catholics could matter greatly.

The Catholic bishops of Pennsylvania recently sponsored a day of prayer and fasting in response to what they called the “unprecedented and gross infringement” of religious liberty by the Obama administration. The Catholic Conference of Ohio endorsed a state legislative resolution urging Obama to rescind the HHS mandate.

Is it really part of Obama’s battleground-state strategy to disassemble Franklin Roosevelt’s Democratic coalition in the middle of a tight reelection campaign? Did he think traditional Catholics would depart quietly?

Well, they haven’t. Forty-three Catholic institutions, including the University of Notre Dame, Catholic University and the archdioceses of New York and Washington, filed suit Monday in federal court to overturn the mandate. The U.S. Conference of Catholic Bishops has called all Catholics to 14 days of “prayer, study, catechesis and public action” on religious liberty from June 21 to the Fourth of July. This is smack in the middle of the presidential season. It also, not coincidentally, starts around the Feast of St. Thomas More, who said, “I die the king’s faithful servant, but God’s first.”