Middle Eastern Christian communities face extinction, and the results for the stability and peace of the region would be devastating, said an advocacy group asking Americans to speak out on their behalf.

"They have been there since the time of Christ, and they are now arguably in the time of their greatest need," said Kristina Olney of the advocacy group In Defense of Christians. "We are basically seeing history erased."

In Defense of Christians is a non-profit that raises awareness of the plight of Middle Eastern Christian communities threatened by sectarian conflict and the terror group ISIS.

The advocacy group organized a "Day of Action" for those communities on Feb. 25, imploring U.S. Christians to pray and sacrifice "in the spirit of Lent" and give to charities that help Middle Eastern Christians. They have also called participants to contact members of Congress, the White House, and the State Department to advocate for the persecuted.

Olney spoke to CNA about the Day of Action and the current situation for Christians in the Middle East, where millions have been displaced and many more are threatened with harsh daily realities of persecution and violence.

These communities are the glue of society – if they are eradicated, the whole region will suffer, Olney argued.

"The Christian communities in the Middle East as well as the other vulnerable religious minorities who have also suffered persecution in the region, are essential not only as bedrocks of civilization in the region, but also filters for de-radicalization."

The initiative is even more significant after the recent beheadings of 21 Coptic Christians in Libya by ISIS, as well as the reported abduction of an estimated 150 Christians in Syria by the same militant group.

"This issue is not a priority for the U.S. administration," Olney said. "The American people need to understand that ultimately if this issue is not championed by them, it isn't just naturally going to be championed by our government."

For instance, she noted that Congress created a special envoy for persecuted religious minorities in the Middle East to report directly to the president. But President Obama has not nominated a candidate to fill the position.

"So we are asking our base of supporters across the country to call the White House and ask that an appointee for this position be named," Olney said.

In Defense of Christians also wants more accountability for U.S. aid promised to the beleaguered Christians. The State Department admitted in December that the overall needs of Iraqi refugees were not being met, in the dead of winter.

Last month, the United Nations' refugee arm UNHCR – which has been giving the majority of aid to the refugees – reported a 40 percent shortfall in aid, Olney pointed out.

"If that aid does not reach those communities in the coming months, then there are going to be significant ramifications for the refugees in the region, because many of them don't have shelter, basic survival needs," Olney said.

Ultimately, she stressed, U.S. Christians must take the lead in educating everyone about the importance of the issue.

"You can't defend what you don't know," she said. "People simply don't know the history of those communities."

"To remove them would be to remove a part of history," she added. "If in America we were to have our monuments bulldozed, if we were to have our Constitution burned, those are things that would affect everyone, because it's our national history."

These sentiments were shared by Archbishop Joseph Kurtz of Louisville, who heads the U.S. Bishops' Conference, and Bishop Oscar Cantu of Las Cruces, chair of the bishops' Committee on International Justice and Peace.

Earlier this week, the two bishops sent letters to the Obama administration and Congress calling for more to be done on behalf of Christians in the Middle East.

The U.S. could counter ISIS with military force, the bishops said, but within the parameters outlined by Pope Francis and the Holy See – that the use of force be "proportionate" to the threat, "discriminate," and used under "international and humanitarian law."

And military action is not enough, Archbishop Kurtz and Bishop Cantu insisted. They emphasized the "overwhelming" needs faced by refugees and called for the U.S. to increase its assistance, including by accepting "its share" of refugees unable to return to their homes.

The U.S. should also emphasize a foreign policy of religious freedom, human rights, and inclusion of minority sects in civic matters, the bishops continued.

"Attacks on religious and ethnic minorities are attacks on the health of an entire society," they said. "The rights of all Syrians, Iraqis, Libyans and others in the region are at risk from the current situation."