Ferguson is (uncharacteristically) unpersuasive in his opposition. He writes, “Members will be forced to tap the federal treasury every time they want to investigate new endive-growing techniques in Kuala Lumpur or sweatshops in Bangkok. And demagogic critics will loudly complain that taxpayers foot the bill for congressional globe-trotting.

“Stung by the new globe-trotting scandal, congressmen will stay in Washington. And they will become even more insulated and out-of-touch than those same demagogic critics say they already are. Demands will be heard for congressmen to break free of the ‘Washington cocoon.’ Technical exemptions will have to be made to the old rule. The ethics jungle will thicken in keeping with a universal truth: Rules beget more rules.”

Lobbyists may be paying for trips to Bangkok, but I doubt it’s to investigate sweatshops. (The trips tend to make the congressmen more “insulated,” not less.) Would a ban on privately funded travel really get rid of a lot of worthwhile trips? I doubt it. And I’m less concerned than Ferguson that voters will resent worthwhile trips: I think that a congressman could defend a trip to investigate sweatshops if he documented that he was spending most of his time on the trip doing that. Finally, do we really think there will be demagogic demands that congressmen be able to take some privately funded trips? Ferguson’s scenario piles improbability on improbability.