This article originally appeared in the CQ Weekly 2012 Republican Convention Guide.

Campaign finance watchdog groups are warning Republican members of Congress in Tampa this week to steer clear of convention-related events held by lobbyists in their honor. In a letter sent to every House member earlier this month, the groups, which include Public Citizen and Common Cause, say attendance would violate a 2007 law overhauling rules that govern how lawmakers and lobbyists interact.

But the House Ethics Committee, in its own guidance, offered somewhat contradictory advice. It agrees that a representative may not attend an event held solely to honor him or her, but it says House members may attend events honoring more than one of them, such as those for a state delegation, House committee or caucus.

Senators weren’t covered by the 2007 law’s party convention strictures. But the chamber has adopted its own rules that prohibit senators from attending such events. The one big exception is when a senator is a featured speaker.

The discrepancy has the advocacy groups ticked off. In their letter, they call the House guidance “an absurd interpretation of the rule because it would prohibit the narrowest form of the problem while ‘authorizing’ much broader efforts by lobbyists to buy access and influence.”

The language in the law, however, would seem to back up the Ethics Committee. It says House members may not “participate in an event honoring that member” if the event “is directly paid for by a registered lobbyist.”

The latter phrase raised another issue that some watchdog groups are eager to address: allowing lobbyists to pay another organization, which does not lobby, to host the event. The advocates’ letter says the Ethics panel’s ruling violates the “clear spirit” of the 2007 law.

The groups, which are tracking such events, can take heart from separate guidance from the Senate secretary and House clerk. Both say the 2007 law does require organizations that lobby to report on their periodic disclosure forms how much they spend on events honoring lawmakers.