Are you infuriated enough about an issue to send letters to Congress members all over the country? Are you incensed enough to fill out that advocacy group’s postcard and mail it to members of the House and Senate leadership?

Well, here’s something that’ll really get your blood boiling: Your letters are probably being ignored.

It's an old, seldom-discussed practice in Congress. In a "snail mail system," letters are sorted when they come into an office. Mail that is identifiably from people who live in the district is put aside to be answered. Mail from outside the district is sent on unread to the letter-writer’s representative, regardless of whether the communication is targeted specifically to the first lawmaker. Mail without identifiers is trashed, says one Michigan representative's staffer who wanted to remain anonymous.

In all, according to a Congressional Management Foundation survey, 87 percent of House offices and 74 percent of Senate offices screen out non-constituent mail, even if the member’s work affects the whole country. And those percentages will increase as the deluge of e-mail increases, predicts Richard Shapiro, executive director of the foundation. Among members of Congress "there's a view that it's not worth spending a lot of time" on non-constituent mail, he said, because they feel those views are insignificant compared to national polls, and that they do not represent the opinions of those in a congressional district or in a senator’s home state.

One representative, Barney Frank of Massachusetts, is publicly adamant about steering clear of e-mail because of all the non-constituent mail it would produce. A Democrat whose 4^th District in Massachusetts includes some of the Route 128 technology corridor, Frank told 5th Estate in a faxed response that "my prime responsibility is to answer those communications that come to me from people in my district." Frank said that while members of Congress have "some time and energy left over" to deal with mail from non-constituents, "we cannot with our small staff respond to people all over the country on complex issues."

Shapiro says that in the case of e-mail, lawmakers are often trying to avoid advocacy groups' efforts to inflate the amount of support they receive from individuals. "If some organization … is trying to get the opinions of a hundred people sent 500 times to 535 congressional offices, why should offices provide a forum for that kind of lobbying?" he said.

But Peter Sepp of the National Taxpayers Union says that Congress members should not ignore non-constituent mail – whether it's paper or electronic. "Members of Congress are not only elected to represent the 400,000-500,000 people in their district, they're elected to represent the national interest," he said. "Maybe getting feedback from people outside their district will tell them that parochial issues sometimes have to take a back seat when federal tax dollars are involved."

Congress also routinely cold-shoulders postcards, Shapiro said. "The view that typewritten postcard is less valuable than a handwritten note, because [with a note] the individual has clearly taken time to write a personal letter to their congressman." E-mail "postcards" that read like form letters also get the same treatment, he said.

Sepp bristles at this practice. "I think [Congress members] resent e-mail because it's not as easy for them to tell [whether it is a constituent mailing] or as easy for them to ignore it. To that I honestly have to confess that I don't really care," he said.

Congress, however, seems to be keeping the barriers to non-constituent mail firmly in place, and extending them to e-mail.

At Rep. Bill Thomas's office, "when we have a situation that we think is not a constituent, we send the e-mail along to the office we think it belongs in," says Jason Poblete, communications director for the House Administration Committee, which Thomas, a Republican from California, chairs.