This approach was guided by an underlying philosophy that if both sides had enough weapons, neither would use them because doing so would guarantee mutually assured destruction.

To be sure, the thought of Bill Cheney, Fred Becker, Ed Yingling and Camden Fine having access to nuclear weapons brings to mind images of Peter Sellers in "Dr. Strangelove."

That said, while all four trade associations have avoided the use of weapons, they've been doing the next best thing: dramatically ramping up their donations in recent election cycles. The political action committees of the ABA and CUNA are among the 20 biggest campaign donors (No. 7 and No. 17, respectively, according to the Center for Responsive Politics), and there is considerable overlap among the beneficiaries of their largesse.

A good case study is House Deputy Whip Debbie Wasserman Schultz (D-Fla.).

She recently circulated, at the urging of banks and credit unions, a dear colleague letter urging House conferees to remove a provision in the financial overhaul bill giving the Federal Reserve the power to regulate interchange rates. The provision ultimately stayed in the final version of the bill. The PACs of the two major credit union trade groups and the two biggest bank trade associations have all given her money this cycle.

The PACs of the ABA, CUNA, ICBA and NAFCU gave the lawmaker $4,000, $2,500, $10,000 and $1,200, respectively, during the 2009-2010 campaign cycle.

None of the large associations for the retailers have given Wasserman Schultz money during the current campaign cycle.

But overall, PACs representing retailers have given $3.2 million to lawmakers and challengers in the 2009-2010 cycle. While that is considerably smaller than the amount given by credit union and bank PACs ($5.9 million) it is enough to make the retailers a force to be reckoned with and helped them win the latest battle over interchange.

When it comes to raising the cap on member business lending, it's a classic case of lawmakers having to choose between friends. Wasserman Schulz, isn't one of the co-sponsors of the House version of the bill to raise the cap on MBL.

Of the 295 House candidates that CUNA's PAC has contributed to this campaign cycle, all but 71 also received money from the ABA's PAC.

Lobbyists sometimes minimize how much special treatment they receive as a result of their campaign contributions. Quid pro quos are illegal and unethical but the current campaign finance system almost requires groups with business before Congress to make campaign contributions.

However, because there are so many different individuals and groups making contributions, it is harder for one interest group to have disproportionate sway on an individual lawmaker.

"If you alienate a donor, there are three waiting to replace him. There's no such thing as an irreplaceable donor," University of Virginia political scientist Larry Sabato said.

Politicians often deny that contributions sway their vote, but in moments of candor some are more forthright.

Former Sen. John Breaux (D-La.) was once asked if his vote was for sale, he replied: "I can't be bought, but I can be rented."

When attendees of NAFCU's annual meeting spend $225 to play in a golf tournament and/or $150 to take a Lake Michigan cruise they will fill up the coffers of NAFCU's Political Administrative Fund. Much of that money will go toward making contributions that will help the credit union movement flex its political muscle.

It's not, however, clear whether that muscle will make the association strong enough to beat other interest groups that are being equally vigilant about pumping iron.

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