Time is running out for nonprofit leaders to protect the charitable deduction from changes they fear would cripple charitable giving next year.

Lawmakers have until December 31 to avert the so-called “fiscal cliff,” a combination of automatic spending cuts and tax increases that has taken up virtually all attention on Capitol Hill since Election Day.

“The charitable sector is an extremely diverse community with different opinions. One area where we’ve come together is the charitable deduction,” Independent Sector (IS) President and CEO Diana Aviv said.

President Barack Obama has in the past proposed limiting tax deductions to 28 percent for people in the two highest tax brackets. Republicans, led by House Speaker John Boehner (R-Ohio), are batting around the idea of a capped dollar amount on all deductions, though no specific proposal has been presented yet.

Reducing the deduction from 35 percent to 28 percent could result in between $2 billion and $7 billion less for the charitable sector per year, Aviv said, while a dollar cap on deductions could be even more detrimental. “If nobody used a charitable deduction because they used others, it could be a loss of $78 billion,” she said.

About 370 people listened to nine industry leaders speak during an hour-long conference call Wednesday sponsored by Independent Sector and Leadership 18. Earlier in the day, IS issued a statement supporting "an approach based on equitable buren sharing, and we believe a plan that includes a modest tax increase on the 2 percent of American who can most afford it offers the best hope of moving forward in a fair and balanced way."

Fr. Larry Snyder, CEO of Catholic Charities USA, based in Alexandria, Va., said there were misconceptions about the charitable deduction. “People say this is a millionaire’s benefit, but that’s not true at all,” he said. “We get over $800 million in donated revenue per year, and the majority of that comes from people donating $1,000 or $2,000 or $5,000,” he said. “If any part of that money goes away, agencies have to make some difficult decisions about programs.”

Presenters stressed that the charitable deduction would ultimately affect not only those making the deductions, but the charities receiving the deductions and their constituents benefiting from the deductions. “It’s really going to be the communities who are the losers in this,” said Nina Tunceli, chief counsel for government and public affairs for Washington, D.C.-based Americans for the Arts.

It is critical that the sector lean on lawmakers to exclude the charitable deduction from revenue discussions. “We have a lot of work to do to get (lawmakers) to understand the impact of changes to the deduction on us and the people we serve,” said Russ Shay, director of public policy for the Land Trust Alliance in Washington, D.C. Shay suggested that as CEOs and upper management talk to donors this giving season, they stress the importance of donors asking their representatives to protect the charitable deduction.

“We have to do everything we can to encourage folks to share impact,” added Gloria Johnson-Cusack, executive director of the Alexandria, Va.-based Leadership 18, a coalition of charity CEOs. “We can’t assume policy leaders understand it,” she said.

The good news is there is still time to impress upon Congress and the White House the importance of keeping the charitable deduction intact. Most of the presenters expected talks about the fiscal cliff to continue all the way until zero hour, Dec. 31. “The window is not yet closed,” said Aviv. “The degree to which lawmakers and the White House hear from you could shape things. We have the ability to shape our future.”