Groups Seek Disclosure of Term Limit Backers : Prop. 164: Measure’s proponents are accused of hiding funding sources, including alleged support by Kansas billionaires.

California Common Cause declared Friday that leaders of the Proposition 164 campaign to limit congressional term limits are hiding the sources of their funding and called on them to “come clean.”

In a news conference, representatives of Common Cause, the Sierra Club and the League of Women Voters took turns challenging the motives of the driving forces behind the measure to limit the tenure of California’s congressional members to six years.

“Why are they trying to hide where their money comes from?” asked Kim Alexander of California Common Cause, a citizens lobbying group. “What are they hiding from the public? Why don’t they come clean and tell us who is behind U.S. Term Limits.”

More than 40% of the funding--at least $478,000--for California committees backing California’s Proposition 164 has come from a Washington-based group called U.S. Term Limits.

Because of what Alexander called “loopholes” in state campaign finance reporting laws, U.S. Term Limits is not obligated to name donors or give a breakdown of how much each has given.

Alexander said that in addition to money that has flowed into California, U.S. Term Limits has given at least $350,000 to campaigns for term limits in eight other states this year.

Jeff Langan, a U.S. Term Limits spokesman, did not return calls from The Times on Friday. The group’s president said in a letter to The Times that 14,000 people have given small donations.

In addition, the organization has released the names of 51 people who are said to have given $1,000 or more. Langan said these 51 larger donors have given a total of $1.6 million, for an average gift of $31,372.

But Langan did not reveal the specific amounts that each of the 51 have given, or say whether any single individual gave more than $1 million to the effort.

Alexander charged that conservative Kansas billionaires Charles and David Koch, who run the $19-billion Koch Industries, a privately held oil and gas company, appear to be behind the campaign to limit terms in California and other states.

Though the Kochs do back term limits, their spokesmen deny that they are involved in the current campaigns. They distanced themselves from the issue after their open involvement became the focus of attacks by foes of a term limit measure in Washington state last year.

One of the connections between the Kochs and U.S. Term Limits is that the U.S. Term Limits group obtained its mailing list of potential donors from a Koch-funded group, Citizens for Congressional Reform.

Polls leading up to Tuesday’s election show Proposition 164 heading for victory. But Michael Paparian of the Sierra Club noted that voters may become less supportive if they conclude that the California congressional delegation has been “incredibly effective at stopping offshore oil drilling, promoting clean water laws and clean air laws--all of which the oil industry has serious problems with.”