Minnesota Rep. Collin Peterson, the top Democrat on the House Agriculture Committee, told the crowd more grass-roots pressure will be needed in order to force the GOP leadership's hand before the end of the current Congress.
So far "the groundswell is not out there," he warned. "This rally is a good starting point but what we need -- what is going to change this -- we need 100 or 200 calls from people in their districts to these members. That's what is going to change this."
"If you don't do that, we're not going to get a farm bill," he said. "It's that simple."
A number of conservative leaders want to wait until after the November election, at which point they hope full Republican control of Congress and the White House will allow them to draft a bill more in line with their ideological preferences.
Rep. Tom McClintock, R-California, argued Wednesday that Congress "shouldn't be subsidizing any product."
"It has nothing to do with how much they're making or not making," he said at the panel discussion with Huelskamp. "Prices convey an enormous wealth of information that is absolutely essential to consumers to make rational decisions in the marketplace."
For their part, top Senate Republicans have indicated support for a short-term extension if the Senate's five-year bill can't get through the House.
"I represent a state in which agriculture is important," Senate Minority Leader Mitch McConnell, R-Kentucky, said Tuesday. "I don't believe that we ought to let the current farm bill expire if we're unable to at this point to pass a replacement."
The head of the House Agriculture Committee -- Oklahoma GOP Rep. Frank Lucas -- told CNN on Wednesday "there's a growing probability" that a one-year extension is "the most practical thing."
"I believe some kind of action will happen before we go home (for the campaign), and it's my intent to help to make it happen," he said. "Something has to happen."