On June 1, the film "For Greater Glory," starring Andy Garcia, made its debut in U.S. theaters. The movie tells the story of the Cristero War in Mexico in the late 1920s. The popular rebellion rose up against the Mexican government's efforts to throttle religious freedom in order to curb the exercise of religion and secularize Mexican society. In the savage clash that followed, Catholic priests and nuns were executed, some even tortured and hanged from telephone poles.

Religious freedom remains at risk today. In Iran, Christian Pastor Youcef Nadarkhani languishes in prison, sentenced to death for allegedly converting from Islam to Christianity. In China, the Shouwang church - a thousand-member unregistered "house church" that refuses Communist government oversight of its affairs - has met outdoors since Easter 2011 when officials seized its meeting space and placed the pastor under house arrest.

Thankfully, religious believers in America can stand far more confidently on our constitutional foundation of religious liberty. Americans enjoy the freedom not only to worship according to the dictates of conscience but also to live according to those beliefs as we engage in public life.

Such a blessing is extraordinarily rare in the course of human history, and each new generation of Americans has the responsibility to guard it. We should beware the danger of erosion in the foundation of American freedom as government oversteps its constitutional limits.

In the two weeks leading up to Independence Day, many Americans have been calling attention to religious liberty by participating in the "Fortnight for Freedom," a celebration of religious freedom and call to preserve it against erosion.

For months, religious leaders have expressed concerns about recent actions that they claim would undermine religious liberty. In one instance, the administration argued at the Supreme Court that the government can interfere with a church school's freedom to determine who would qualify as a minister to teach the faith. In another, the Department of Health and Human Services refused to renew a Catholic service organization's grant to help human trafficking victims because it refused to refer women for abortions, despite the group's track record of success and high rankings in the application process.

The most concerning development of recent months is the HHS mandate that nearly all insurance plans must cover abortion drugs and contraception, even though many Americans have religious and moral objections to these. The HHS mandate is one of the first steps in implementing the massive new 2,700-page health care law. It includes the narrowest of religious exemptions, shielding only houses of worship from government requirements that violate their conscience. Religious employers such as Catholic hospitals, Christian schools and faith-based soup kitchens do not qualify for the exemption. Failing to comply with the mandate will result in massive fines.

No wonder the rule has provoked intense, widespread and sustained opposition from Catholic, Protestant and Jewish groups, as well as others.

Religious freedom requires that the government not interfere with religious faith, nor with the works it inspires. When a policy threatens religious liberty, it often threatens freedom more generally. .

The conflict between faith and state in the United States is civil, not - thankfully - violent, as it is elsewhere around the world. But our conflicts are civil because of the order we established under the Constitution. The best way to preserve social and religious peace in America is to respect the Constitutional order, and ensure that government remains limited.

We all enjoy religious freedom, so we should all be prepared to defend it. During the Fortnight for Freedom, Americans across the country will be doing just that by teaching the next generation about religious liberty, while serving and praying for their communities.

Throughout American history, the bell has been a symbol of liberty. During the Cristero War, the government silenced church bells. It is fitting that at the finale of the Fortnight for Freedom church bells across the country will ring at noon Eastern time, proclaiming: Let religious freedom ring!

Jennifer A. Marshall is director of the DeVos Center for Religion and Civil Society at The Heritage Foundation.