Goldman Sachs

(GS) - Get Report

is the third largest donor to Senate Agriculture Committee Chairman Tom Harkin (D., Iowa) over the course of his career, while giant agricultural conglomerate

Archer Daniels Midland

(ADM) - Get Report

is number six, according to OpenSecrets.org.

This fact might seem odd to lay folk, but the agriculture committees in the Senate and the House of Representatives actually matter a lot to Wall Street banks like Goldman,

Morgan Stanley

(MS) - Get Report

and

JPMorgan Chase

(JPM) - Get Report

that have large derivatives trading operations.

That is because the agriculture committees oversee the Commodity Futures Trading Commission, which regulates futures markets like

CME Group

(CME) - Get Report

and

IntercontinentalExchange

(ICE) - Get Report

.

Though there is widespread support for a merger of the CFTC and the

Securities and Exchange Commission

, which oversees stock exchanges like

NYSE Euronext

(NYX)

and

Nasdaq OMX Group

I:IXIC

, there appears to be no hope of that actually happening, Washington observers say.

"You'd be hard-pressed to find anyone who doesn't think combining the SEC and CFTC wouldn't be a plus," says Brian Cartwright, former SEC general counsel. "But you'd be hard-pressed to find anyone knowledgeable about Congress who believes that outcome is likely."

That's because the House and Senate agriculture committees don't want to give up campaign contributions from big financial firms, says Marc Lackritz, a lecturer at Georgetown University and former president and CEO of the Securities Industry and Financial Markets Association, Wall Street's main lobbying organization.

"They fight tooth and nail to maintain that jurisdiction, notwithstanding the fact that 90% or 92% of all futures now are financial; they're not agricultural," Lackritz says.

Securities and investment firms have given Harkin nearly $800,000 in his career, according to OpenSecrets, nearly as much as the $1.1 million he's gotten from agricultural companies. Lawyers and law firms have given him more than $2 million. A Harkin spokeswoman did not respond to calls and email messages seeking comment.

Harkin's counterpart in the House of Representatives, Collin Peterson (D., Minn) appears less vulnerable to charges that campaign contributions are influencing his views on policy. He has received $90,000 from securities firms and $125,000 from commercial banks, though that is far less than the $1 million he's gotten from agricultural companies.

Nonetheless, Peterson strongly argued at a February hearing of the House Agriculture Committee that the CFTC should be the primary regulator for the $30 trillion

credit default swaps

market, arguing that the SEC is "behind the curve" and the

Federal Reserve

is "not a police officer." He said CFTC oversight of futures markets "is working," -- a view many observers would dispute.

"I don't think the CFTC is a very strong regulator at all. I think most people see the CFTC as kind of a phantom agency that does very little," says John Coffee, professor at the Columbia University School of Law.

Though Coffee also believes merging the CFTC and SEC makes sense, he says it has little of any chance of occurring.

"I've been told by members of the Senate Banking Committee, which has the SEC jurisdiction, that they've not heard of any push coming from the White House for this," he says.

At a press conference March 5, House Financial Services Committee Chairman Barney Frank (D., Mass) said a merger of the two agencies was not on the immediate agenda because it came with "political heat."

Frank spokesman Steven Adamske says Frank meant that he could not propose a merger of the two agencies because it would look self-serving.

"What he meant by that was he cannot do that because it looks like he is empire building by shifting one thing from one committee to the other," Adamske says, adding that it would also create turf battles between congressional committees, commissioners and lobbyists.

Adamske rejects, however, that those turf battles are related to campaign money, notwithstanding the views of Coffee, Lackritz and Cartwright, among others.

"I don't accept that that's why people do things like that. That's sort of like saying 'Why do we do certain things in our committee?' And journalists who put down that we did certain things and then happen to note that members took certain levels of contributions. It's not cause and effect. It's not anything," he says.