Federal Election Commission filings released this week showed that conservatives groups are amassing an ocean of cash for the 2012 presidential campaign. Thanks to the likes of the Koch brothers, the Walton clan and other of the usual suspects on the right, in 2011 conservative SuperPAC's outraised their liberal counterparts by more than seven to one. But if they win, rich Republican donors could more than get back the millions they invested. As it turns, just one law they are trying to buy - the elimination of the estate tax - could put billions of dollars back into their families' bank accounts. Of course, that gaping hole would have to be filled by all other American taxpayers.

As Mother Jones reported, as of December 31, 2011 conservative SuperPAC's reaped $60 million of now-unlimited contributions, compared to just $8 million for liberal groups. That tidal wave of corporate cash and play money from the wealthy has filled the coffers of Karl Rove's American Crossroads, Mitt Romney's Restore the Future, Newt Gingrich's Winning the Future and a litany of other right-wing SuperPACs. And as Amanda Terkel detailed, at a secret conclave last week, the Koch brothers pledged to raise much more to defeat President Obama:

At a private three-day retreat in California last weekend, conservative billionaires Charles and David Koch and about 250 to 300 other individuals pledged approximately $100 million to defeat President Obama in the 2012 elections.

A source who was in the room when the pledges were made told The Huffington Post that, specifically, Charles Koch pledged $40 million and David pledged $20 million.

But that figure is chump change compared to the eye-popping return on investment the Kochs can expect if their side wins in November. Ending the estate tax, a policy endorsed by Mitt Romney and every other Republican presidential candidate, would literally be worth billions of dollars to the heirs of Charles and David Koch. As ThinkProgress explained last year:

According to a quick back-of-the-envelope calculation, the Koch brothers' heirs' would save a combined $17.4 billion in estate taxes thanks to Romney's plan.

Each of the Koch brothers -- Charles and David -- is worth about $25 billion. They are each married, so they would receive an exemption on the first $10 million that they pass down, and then theirs heirs would pay a 35 percent tax, or $8.7 billion, on the rest of their vast fortunes.

Now, this is an exceedingly rough calculation, as it's almost certain that the Koch's have engaged in extensive estate planning and would pay nowhere near that amount. But 35 percent is the rate on the books, and Romney's plan to eliminate the estate tax entirely would undeniably save the Kochs a boatload of money.

Here's why. Despite Republican mythology about family farms and businesses being lost to the so-called "death tax," by 2009 only 0.24 percent of estates even paid the levy. And that was before the December 2010 compromise President Obama inked with Congressional Republicans extending the Bush tax cuts further slashed the estate tax. The reduced 35 percent tax is now applied only to couples with estates greater than $10 million, a change which will cost Uncle Sam roughly $15 billion a year. Now, the Tax Policy Center calculated, only 0.1 percent of estates are impacted. Only 50 family farms and small businesses will be affected, and they contribute "less than one tenth of 1 percent point of the total revenue the tax will collect." Who pays the estate tax?

TPC estimates that 8,600 individuals dying in 2011 will leave estates large enough to require filing an estate tax return (estates with a gross value under $5 million need not file a return in 2011). After allowing for deductions and credits, an estimated 3,270 estates will owe tax. Roughly 90 percent of these taxable estates will come from the top ten percent of income earners and nearly half will come from the top one percent alone./em>

Estate tax liability will total an estimated $10.6 billion in 2011. The top ten percent of income earners will pay 98 percent of this total. The richest 1 in 1,000 will pay $5.4 billion or 51 percent of the total.

Among that richest 1 in 1,000 are the Koch brothers and the family behind Walmart, the Walton clan.

That's one reason why Wal-Mart heirs Alice Walton and brother Jim Walton each contributed $100,000 to Mitt Romney's SuperPAC. After all, the six members of Walmart's founding family are worth an estimated $69.7 billion, a sum equal to the total wealth ofthe bottom 30 percent of Americans. As Vermont Senator Bernie Sanders explained in his now famous December 2010 filibuster, the elimination of the estate tax could save the Walton family alone $32.7 billion.

Of course, the Walton crusade to the end the estate tax didn't just start last year. As USA Today reported back in 2005:

Led by Sam Walton's only daughter, Alice, the family spent $3.2 million on lobbying, conservative causes and candidates for last year's federal elections. That's more than double what it spent in the previous two elections combined, public documents show.

The Waltons have joined a coterie of wealthy families trying to save fortunes through permanent repeal of the estate tax, government watchdogs say. The election of President Bush and more conservatives to Congress gave momentum to the long-fought effort. The Waltons add more.

As the Arkansas Times pointed out, the 2010 reduction in the estate tax, if made permanent, would ensure that Sam Walton's clan will keep billions out of the hands of Uncle Sam:

Please note that the cut in the top estate tax, from 45 to 35 percent, will be worth a cool $9 billion at current values to just the top five Walton estates. 9 BILLION. Who'll pay for that lost revenue (not just from Waltons but Kochs, etc.) over the years? The working schlubs, that's who.

Thanks in part to the efforts of the "Senator from Walmart," Blanche Lincoln, President Obama's concession in December 2010 gave the Waltons won a huge victory. If they get their way, it won't be their last.

It's worth noting that Mitt Romney, Wall Street's favorite for 2012, will also benefit from the elimination of the estate tax, just not on as grand a scale. The heirs of the 250 Million Dollar Man could reap an $84,000,000 windfall, more than enough to offset the $45 million of his own money Mitt Romney blew in his failed 2008 presidential campaign.

It's worth pointing out that America's rich and famous won't be paying the full estate tax anyway. After all, Mitt Romney has apparently succeeded in setting up a $100 million trust fund for his sons, tax-free. As President George W. Bush put it in rejecting calls to raise taxes on the wealthy duiring his 2004 reelection campaign:

"The really rich people figure out how to dodge taxes anyway."

If the Republican presidential candidates and their fabulously wealthy SuperPAC donors get their way in cutting income taxes, eliminating the capital gains taxes and ending the estate tax, Bush's really rich won't have to work very hard to dodge Uncle Sam. If the Kochs and the Waltons succeed in getting the best government money can buy, the rest us will have to pay for it.

(This piece also appears at Perrspectives.)