A pro-Israel lobbying group has found a loophole in the rules limiting the ability of lobbying groups to pay for congressional travel - a loophole large enough that they are one of the leading sponsors of such travel.

The American Israel Education Foundation (AIEF) paid for more than 50 lawmakers and staff of both parties to travel to Israel in August, according to the trip disclosures in LegiStorm's database. Travelers included House Majority Leader Steny Hoyer (D-Md.) and Rep. Michele Bachmann (R-Minn.).

AIEF is the fundraising arm of the American Israel Public Affairs Committee, or AIPAC, an influential lobbying group. Despite tough rules forbidding congressional travel paid for by lobbyists, AIPAC gets around the ban by having its nonprofit arm pay for the trips.

The House ethics manual states that the travel restrictions "severely limit the ability of Members and staff to accept travel from an entity that employs or retains a registered lobbyist." The only exemptions spelled out in the guidelines are trips sponsored by institutes of higher education.

However, even though AIPAC's primary purpose is lobbying, its nonprofit arm appears to provide a loophole for sponsored travel. AIEF is able to fill out the House's travel sponsor certification form attesting that it "does not retain or employ a registered federal lobbyist."

Despite the different name and its non-profit status, AIEF seems to be essentially indistinguishable from AIPAC, which does employ registered lobbyists. The two organizations share the same address, and AIEF is described on AIPAC's web site as a "charitable organization affiliated with AIPAC."

The form filed by a traveler on an AIEF trip from December lists AIPAC directors as tour participants and lists AIPAC's Jeruselem office as a contact number. Until this year, AIEF officials who filled out the trip certification forms used aipac.org email addresses (they now have emails with an aiefdn.org domain). The most recent filing with the IRS shows AIPAC transferred more than $14 million to AIEF during the 2008 fiscal year that was "used in supporting educational programs."

When Congress was working on strengthening the travel ban in 2006, reports indicated AIPAC lobbied for an exemption from the ban on lobbyist-sponsored travel. The organization did not receive a specific exemption, but the loophole on allowing non-profit travel allows the organization to continue to sponsor travel. In fact, since the beginning of 2008, AIEF has sponsored 134 trips at a cost of more than $1.4 million - more money than any other sponsor has spent on trips for Congress, according to LegiStorm's database.

This post is part of our occasional series "Storm Tips," in which we highlight interesting items we stumble across in our raw records.