**UPDATED**

Last summer conservatives rolled their eyes when they read in Politico that Rep. Eric Cantor, then serving as GOP whip, suggested “Republicans may roll back their ban on earmarks.”

The self-imposed moratorium, enacted last March, was a triumph for conservatives in their long-running battle with House appropriators. Now it appeared to be under attack from the future House majority leader.

The disappointment among conservatives — not to mention Tea Party-backed candidates across America — must have resonated with Cantor. Just six week later he penned a piece for Politico declaring war on pork-barrel projects and endorsing a new moratorium in the 112th Congress.

Cantor’s outspoken opposition to earmarks put their advocates on the defensive. It set the stage for last fall’s confrontation among Senate Republicans and this week’s decision by Senate Appropriations Chairman Daniel Inouye (D-Hawaii) to effectively end earmarks for two years.

Why is this relevant? The GOP is facing another spending showdown — this time over $100 billion worth of cuts promised in the Pledge to America.

Republican leaders have put forward a plan that cuts non-security spending by $58 billion, a noble effort, but still $42 billion short of their campaign promise. (They also cut $16 billion from security funding.)

Conservatives believe $100 billion should equal $100 billion. Nearly 90 of them with the Republican Study Committee recently asked Speaker John Boehner (R-Ohio) to stick to the GOP’s promise. And when the debate reaches the House floor this month, RSC Chairman Jim Jordan (R-Ohio) plans to offer an amendment — or multiple amendments — to bring the level of cuts to $100 billion.

Republican leaders, meanwhile, have been noncommittal. Cantor, when asked about it last week following a Heritage Foundation speech, said Republicans would cut $100 billion on an “annualized basis.” (That’s Beltway jargon for cuts that don’t equal $100 billion.)

Here’s the transcript:

Q: I’m wondering if you will support Congressman Jim Jordan’s amendment for a true $100 billion worth of cuts during the CR debate …

A: We are, that’s in reference to the CR debate which will come to the floor Feb. 14. We announced yesterday well in advance. The purpose of my announcing earlier is to make sure that all of our members on our side of the aisle as well as others have the opportunity to proffer their vision as to how we cut the deficit and we have instructed the appropriations, the budget chairman to hold us all accountable for spending levels and we said that we wanted to be at at least 2008 levels as our party committed to during the election in the Pledge to America. We said 2008 levels or less and as you know we are in the situation we are in five months into the fiscal year because the former Democratic House failed to produce a budget and so we have now found ourselves in a Continuing Resolution environment that has held constant 2010 levels. So, we’re looking to the appropriators to come up with their version of how we cut this budget. Again, they have the limit of saying 2008 levels or less, so let’s see what they do and the reason why I am so insistent to say “or less” is because we all have to be very focused on making sure that we find new ways to do more with less. In response to your question, in that context, we are going to accomplish [a] $100 billion cut on an annualized basis.

As they return to Capitol Hill next week, House Republicans must weigh the backlash they will face for violating their $100 billion campaign promise. Anything less than a true $100 billion worth of spending cuts this year will be unacceptable to conservatives.

It doesn’t have to be this way. Cantor showed that great leadership on earmarks and he can do so again on this next big spending debate. That means cutting a true $100 billion and nothing less.

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UPDATE: To his credit, Majority Leader Eric Cantor plans to support additional spending cuts during the House floor debate, when any member will be allowed to offer amendments. “Leader Cantor looks forward to supporting many of those amendments designed to cut spending and grow jobs,” spokesman Brad Dayspring told the Daily Caller.