Senate Democrats thought it was at least worth a shot. With oil industry profits soaring, and consumers frustrated by rising prices at the pump, it seemed like the ideal time to end $21 billion in subsidies to oil companies that clearly don’t need them. When prominent Republican leaders like John Boehner and Paul Ryan hinted they could support a repeal of these industry incentives, Dems were even more encouraged.

But these subsidies have survived a very long time for a good reason — they’ve proven to be all but impossible to kill.

The Senate on Tuesday blocked a Democratic proposal to strip the five leading oil companies of tax breaks that backers of the measure said were unfairly padding industry profits while consumers were struggling with high gas prices.

Despite falling eight votes short of the 60 needed to move ahead with the bill, top Democrats said they would insist that eliminating the tax breaks to generate billions of dollars in revenue must be part of any future agreement to raise the federal debt limit.

“We have to stand up and say, ‘Enough is enough,’ ” said Senator Al Franken, Democrat of Minnesota. “While oil prices are gouging the pocketbooks of American families, these companies are on a pace for a record profit this year.”

Technically, last night’s vote was on the motion to proceed on the bill. Supporters outnumbered opponents, 52 to 48, but with Republicans filibustering the measure, Dems needed a 60-vote supermajority just to initiate a debate on the proposal. They fell eight votes short.

Two oil-friendly Democrats, Mary Landrieu (La.) and Mark Begich (Alaska), voted with the GOP, as did Nebraska’s Ben Nelson who had previously said he opposes filibusters on motion to proceed. Two Republicans, Maine’s Susan Collins and Olympia Snowe, voted with the majority.

Other alleged GOP “moderates,” including Scott Brown (Mass.) and Mark Kirk (Ill.), voted to protect Big Oil’s tax incentives.

The outcome didn’t come as a surprise, since the chances of Democrats finding eight additional votes were remote, but the results are likely to be fodder in the 2012 elections, which is largely why the measure was brought to the floor in the first place.

As for the larger context, it’s also worth keeping in mind that the GOP is moving backwards on the issue. In 2007, the last time Democrats tried to end oil industry subsidies, eight Republicans sided with the majority to scrap the incentives. Late yesterday, there were only two. Given the larger circumstances, the GOP should be more inclined to end the subsidies, not less, and yet, here we are.

It’s also worth keeping campaign contribution totals in mind: “A Center for American Progress Action Fund analysis finds that the 48 senators who sided with Big Oil received over $21 million in career oil contributions, while 52 senators who sided with the American people received only $5.4 million in contributions.”

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.