Both the Senate and House rule that lobbyists cannot accompany lawmakers on travel to such events.

But while the House allows lobbyist and lawmaker to meet up again at a location away from Washington, the Senate cautions that the ethics of doing so depends on “the totality of the circumstances,” a qualification that makes ethics lawyers queasy. Lobbyists and their lawyers prefer broad exemptions that they can use to defend themselves if accused of improper conduct.

Government watchdog groups charge that the House committee has eroded ethics reforms and have called for its overhaul.

“At least two times the House committee has poked a huge loophole in the ethics law,” said Craig Holman, an advocate for Public Citizen, a group that favors stricter ethics rules in Congress. “The Senate has scoffed at what the House has done and the Senate has done so appropriately.

“The House seems to bend over backward to preserve the status quo,” said Holman, who wants the committee to be restructured. Facing pressure from liberal-leaning watchdog groups, Speaker Nancy Pelosi (D-Calif.) has attempted to pass legislation enacting a new House ethics office.

Watchdog groups say the office, which would help the House ethics committee review potential ethics violations, falls far short of what is needed. Even so, Pelosi has faced staunch resistance from members of her caucus who fear such an office could imperil their careers by fanning allegations of wrongdoing made by political opponents.

Government watchdog groups have long been critical of the House ethics committee. While the Senate accepts ethics complaints from outside groups, the House committee does not, an irritating snub for groups such as Public Citizen and the Campaign Legal Center.

Some ethics experts argue that the different approaches do not necessarily mean that the Senate is more serious about enforcing the ethics law passed last year. For example, while the House allows special interest groups to host convention parties honoring a congressional delegation, it does not allow lawmakers to attend lobbyists’ parties as featured speakers. The Senate allows a lawmaker to provide the keynote address at a lobbyist-organized party. Some argue this is an instance where the House is stricter.

Nevertheless, the Senate’s rules for party conventions are generally viewed as stricter.

The Senate has also taken a more fastidious approach to the gift ban. The House has taken no action to modify its tradition of considering gifts worth less than $10 as items of “nominal value” and thus exempt from the ban.

The Senate, however, has drawn a line between drinks and snacks provided during a business conference and those provided at a restaurant or bar. By granting explicit approval only for drinks and snacks provided at a business meeting, the Senate has made clear that buying a senator a cup of coffee at Starbucks or a beer at Charlie Palmer Steak is not OK.

While the House has not taken any specific action to alert lawmakers and staff that they may not accept a cup of Starbucks coffee from a lobbyist, it may still be a good idea for members and staff to check with the committee before doing so.

Sen. Barbara Boxer (D-Calif.), the chairwoman of the Senate Ethics Committee, said that she has tried hard not to undermine the new law.

“We read the law and we’re trying to carry out the spirit and the letter,” she said.

Sen. John Cornyn (Texas), the committee’s ranking Republican, said: “I think the public is skeptical of self-policing efforts, so we have something to prove.”