Or frame your arguments in terms of the national interest. Remember that you are part of the political process. Present your case rationally. Arguments for research and education are not self-evident and support is not an entitlement. At the same time, the political process is highly competitive so don't be shy or ambivalent about asking for support for your cause or for the federal agency that funds your work.
Legislators expect their constituents to be forthright about their interests.
Legislators need to be reminded as often as possible that they have constituents who are concerned about funding for basic research and education and who are paying attention to federal policy. Ask for their active support and offer to help them express it, eg. volunteer to write brief remarks on the importance of mathematics that members can make on the House or Senate floor. Avoid negative arguments. In particular, do not criticize support for other areas of science or suggest they are overfunded. Support for the mathematical sciences will flourish only in an environment where science as a whole flourishes.