Yes if your organization is a public charity. While 501 (c)(3) charities are prohibited from endorsing or opposing candidates for public office (See Ready Reference Page: “IRS Issues New Guidance on Electioneering”), public charities (although not private foundations) are permitted to lobby in support of proposed legislation of the type you describe. (See Ready Reference Page: “Lobbying Rules Create Opportunity for Charities.”) As an aside, according to the original estimates at the time of Hurricane Katrina, the public had given about $2 billion to Hurricane relief efforts. The cost of the relief was estimated to be about $200 billion. Although the estimates may have changed, it is clear that the leverage is with governmental funding, not charitable contributions.