As Washington politicians consider cuts to dedictions as part of a fiscal cliff deal, the charitable tax deduction could end up on the chopping block.

To prevent that, 240 representatives of ministries and non-profit organizations gathered on Capitol Hill Wednesday to fight for this deduction that rewards Americans for their giving to charities, churches, and non-profits.

Following a brief session on lobbying do's and don'ts, they visited lawmakers' offices across Capitol Hill.

Their main message: many of their groups might not survive the drop in giving that would follow the death of the deduction.

"As an organization that serves every zip code in America, the Salvation Army met the needs of more than 30 million people last year. And we are dependent, dependent on public support," Major Darryl Leedom, with The Salvation Army, said. 

Leedom made it clear the loss of that support would be devastating for the people these organizations are seeking to help.

"We are helping families who are hurting: those who are hungry and homeless, those young people who need a place to go after school for education and recreation," he told CBN News.

"And a reduction would be detrimental to our services to those who are hurting the most," he said.