The U.S. Catholic bishops, in a new document citing threats to religious freedom in this country, are calling on all Catholics, including holders of public office, to use all the energies they can muster to defend the religious liberties that our laws and our Constitution guarantee.

The Catholic faithful, along with fellow Christians, Jews and others, are urged to impress on their elected leaders “the importance of continued protection of religious liberty in a free society.”

This campaign is a critically important effort, and it deserves the support of every Catholic in the country.

The bishops also are urging strong involvement by the laity in a nationwide campaign called the Fortnight for Freedom in the two weeks leading to Independence Day, July 4. They’re asking pastors and parish leaders to plan special events during this period, focusing on prayer, teaching and witness.

This, too, deserves the strong support of all.

Religious freedom is the keystone of our freedoms as Americans—the first of our freedoms to be enshrined in the Bill of Rights.

Yet now, as the bishops spelled out in their document, titled “Our First, Most Cherished Liberty,” religious freedom is threatened both here and abroad, and all thinking people should be on guard.

We need only to look back to the creation of this great country to see how fervently the Founding Fathers embraced religious freedom as an essential condition of a free and democratic society.

It was exactly that freedom, in fact, that many of the Fathers’ forebears sought in the early 17th century when they made the treacherous Atlantic crossing to put down stakes in a new and untamed land.

By the late 18th century, when the Constitution and Bill of Rights were drawn, James Madison was describing conscience as “the most sacred of all property” and writing that every man’s religion must be left to his own conviction and conscience, to exercise as his conviction and conscience dictate. George Washington wrote that the establishment of civil and religious liberty on these shores is what led him into battle to secure our freedom.

The bishops, in their document, cite a series of recent developments that have caused alarm. Among them: the HHS mandate for Catholic-affiliated hospitals and other agencies to provide coverage of contraception, sterilization and abortion-causing drugs; immigration laws in several states that would effectively make it a crime to minister to undocumented immigrants; and discrimination against Catholic humanitarian services, which became ineligible for government contracts to serve victims of human trafficking after years of excellent performance because requirements were changed to mandate the provision of abortion and contraceptives.

Lesser known, but just as troubling, was a proposal by the Connecticut legislature to restructure Catholic parishes, and a court decision in New York City to bar small church congregations, mainly Protestant and Evangelical, from renting public school spaces on weekends for their religious services—even though the spaces are available to other community groups.

We could go on. But the point is clear.

Religious liberty is at risk, and we must stand together to protect it.