It’s not every day that members of Congress have to vote on issues that directly pit the interests of their constituents against those of their cash constituents, but such a vote did take place last Thursday and a further examination of the results suggests strongly that money moved the vote.

At issue was a bill that would rescind incentives that went to the oil companies in the late 1990s – a period of relatively low oil prices – for drilling in the Gulf of Mexico. Given the current price of oil, those incentives make little sense any more, critics charged, amounting to a government windfall to oil companies when their profits are already sky high.

My colleague Ellen Miller highlighted the case last week and asked (rhetorically?) whether there might be a money connection in the results. In the face of voter outrage over $3-a-gallon gasoline, the bill passed 252-165 and 67 Republicans jumped ship to vote with consumers and against the oil industry.

Sunlight’s Paul Blumenthal did a quick analysis and found that yes, those Republicans who backed the industry collected about twice as much in campaign contributions from oil interests than Republicans who took the consumers’ side. But Paul looked only at the current election cycle and I wanted to look further back, since I know that major donors tend to seek long-term relationships with members of Congress, delivering money year after year to insure continued support.

Acting on that hunch, I collected some data from the Center for Responsive Politics and found the following: those 67 Republicans not only got more oil money in the current election cycle, but in past cycles as well. Further, a similar and even stronger correlation was found among the 13 Democrats who stood up for the oil companies, despite their party’s position. (Six of those Democrats were from Texas.)

The charts below tell the story. A yes vote supported consumers on the issue, a no vote supported the oil industry. The first chart shows the Republicans, the second shows the Democrats. The numbers listed show contributions in the current election cycle, the last full cycle (2004), and the cumulative totals since 1990 or whenever the member was first elected to Congress.

In short, the more money members collected from the oil industry – whatever their party – the more likely they were to vote the industry’s way, even on a hot-button issue where voters are paying attention.

We’ll take a fresh look at the numbers when this bill reaches the Senate. Stay tuned.