It was quite the ballyhooed reform of Capitol Hill ethics — an explicit ban on insider trading by members of Congress and their aides enacted two years ago in a bipartisan wave of approval by the Senate and House.

Now comes the hard part: enforcement. A legitimate attempt by the Securities and Exchange Commission has been rebuffed by the House with elaborate constitutional contentions. “Repugnant to public policy” is how the chamber’s legal office huffily described the commission’s reasonable subpoenas seeking information from the House Ways and Means Committee and a staff member.

This is more than strange, considering lawmakers’ proud orations when the ban was passed that the public could be confident that federal laws against insider trading would indeed cover lawmakers and their staffs.

Not surprisingly, the commission appealed, and a federal judge in New York has ordered a hearing this week for an explanation from the committee and the staff member suspected of leaking to a lobbyist nonpublic information he heard last year about pending Medicare rate increases. According to the commission, the lobbyist passed this valuable word along to a health care brokerage firm that quickly issued a private alert to clients. A suspicious spike in trading of shares profitable to the clients occurred before the government made its Medicare decision public.