Barack Obama delivered the latest installment earlier this month in an unprecedented amount of outreach to America’s faith communities. He announced his intention to keep, although modify, the “faith-based initiative” begun by President Bush in which government grants for social welfare programs are more readily available to faith-based organizations.

In the wake of the 2004 presidential election, where exit polls emphasized that a voter’s frequency of church attendance was the surest indicator of how he voted, Senator Obama is meeting with pastors and rabbis, going to churches and synagogues, and talking about how faith informs his life and policy views.

Senator McCain as well, albeit to a lesser extent, has engaged in similar outreach recently meeting with prominent faith leaders including the Reverend Billy Graham.

But while each candidate has tried to connect to the critical “values voters,” Messrs. Obama and McCain have said little about the concrete policy issues that directly affect religious freedom in America.

Yes, Messrs. Obama and McCain have spoken a bit about abortion and gay marriage. They’ve also tried to broaden their agendas on those issues as well with Mr. Obama inveighing against poverty and Mr. McCain decrying international sex trafficking as modern moral scourges. But Mr. Obama’s speech about federal funding for faith-based charities was the first time either presidential candidate has touched upon the laws that define religious liberty in America.

Americans enjoy unprecedented freedom to believe and worship as they wish. But in the modern state, with laws and regulations affecting so many aspects of life, religious liberty must be protected for there are a myriad of ways in which it might be undermined.

First, consider the challenges to the religious freedom of individual Americans. While a person’s beliefs are certainly protected by law, many religions demand not just belief but acting, or refusing to act, in certain ways. These include refraining from work on holy days and wearing certain clothing such as a skullcap, turban, or headscarf.

In 1996, President Clinton issued an executive order putting guidelines in place so that federal agency employees can obtain accommodations for their religious needs. But in the private sector, federal law does not currently require an employer to accommodate their employees’ religious needs.

Bipartisan legislation to address such cases has been stalled in Congress for several years. Lobbyists for employer interests object to its placing increased demands upon managers. Some liberal advocacy groups object that the “Workplace Religious Freedom Act” could lead, for example, to a pro-life pharmacist being accommodated not to fill a prescription for contraceptives.

Neither Mr. Obama nor Mr. McCain has taken a position on the matter. But we should know what each candidate thinks about personal religious freedom.

Next consider areas where laws may challenge the religious liberty of houses of worship or other religious institutions such as schools or social welfare charities. Mr. Obama took a stand on one aspect of this issue in his recent address declaring that, under his presidency, a faith-based charity will not be permitted to receive a federal grant unless it waives its right, codified in the Civil Rights Act, to hire people of its particular faith to staff the program being federally funded.

Mr. McCain’s campaign has stated he believes that hiring at faith-based charities should not be subject to new government regulation. This is a clear difference between the two candidates and thus useful to voters.

But the challenge that looms largest to the religious liberty of America’s faith institutions comes from the movement to legally recognize same-sex marriages. This challenge is not from the “moral values” perspective, but from a functional one — how will the law treat religious institutions that object to same-sex relationships?

To date, politicians have addressed this issue by saying that no priest or rabbi will be compelled to officiate at a same-sex service. That is not the issue; any attempt to compel such action would clearly violate the First Amendment. But Catholic Charities in Boston was forced to shut down its century-old program placing children in foster homes because the Church refused, on religious grounds, to make placements with same-sex couples married under Massachusetts law.

The Methodist Camp Meeting Association had part of its tax exemption revoked by a New Jersey township because it refused, on religious grounds, to allow same-sex couples to hold their civil union ceremonies in its boardwalk pavilion. And, while not a sectarian organization, the Boy Scouts have had park permits revoked and other legal privileges denied over the fact that it refuses, with the approval of a Supreme Court decision, to have gay scoutmasters.

Mr. Obama has said he is opposed to same-sex “marriage” but supports civil unions, while Mr. McCain has said this is a matter to be left to state laws. But both candidates must articulate how they believe the law must practically balance competing legal rights in this arena.

After too many years when many thought candidates speaking about faith was out of bounds, the willingness and ease with which faith and its role in a candidate’s life and in the life of our nation is welcome. But just as we insist candidates to lay out their policy proposals for health care, the environment, crime, and taxes, we must ask them to be clear about how they will protect and promote America’s “first freedom” — religious liberty.

Mr. Diament, director of public policy for the Union of Orthodox Jewish Congregations of America, teaches religion and American politics at American University.