Bank lobbyists are really laying it out there. The New York Times reported over the weekend that lobbyists presented their case against an amendment that could reduce debit card fees, the existence of which increase the price of pretty much everything you and I purchase, by threatening to withhold campaign contributions.

The Senate approved a series of amendments unfavorable to the banking industry over the last week, but this one was widely regarded as the most surprising. Meddling in dealings between businesses generally is anathema to Republicans and a relatively low priority for Democrats.

And this was not an easy vote. Lobbyists for the wounded but formidable banking industry made clear to some senators that this decision would affect future campaign donations, according to people who participated in those conversations.

And this is just over an amendment that would allow the Federal Reserve to create rules governing debit card fees. It doesn’t even directly create rules, but allows a body that is often greatly favorable to the big banks to set rules, providing another opportunity for the banks to lobby. Not the toughest amendment, but on a subject so sensitive that banks are willing to use the quid pro quo argument.

These lobbyists continue to make the argument for lobbyist contact disclosure that much more salient. Shouldn’t we know who’s directly trying to bribe members of Congress?