NASHVILLE (AP) - A former Democratic congressman and a prominent Republican political operative on Tuesday called for ending untraceable spending for and against candidates in Tennessee and around the country.

Former Rep. John Tanner said that the lack of controls over spending has created a system of what he called "election by auction."

Tanner acknowledged it would take another legal case to overturn the U.S. Supreme Court's decision in the Citizens United case that allows corporations, unions and wealthy individuals to spend unlimited amounts of money in campaigns. But he urged Congress to change the tax code to eliminate anonymity provisions that can currently shield big donors' identities.

"I don't see how anyone could argue that that is a function of an open, democratic society for people to be able to be anonymous in the political process," Tanner said at a roundtable discussion organized by the Crockett Policy Institute.

GOP political strategist Tom Ingram, who has run the campaigns of U.S. Sens. Lamar Alexander and Bob Corker and Gov. Bill Haslam, said the lack of restraints on spending has made it nearly impossible for anyone without personal wealth to become a candidate for statewide or federal office.

"When I first entered this business, anyone with reasonable intelligence, energy and determination could consider being a candidate," Ingram said.

But now the first question for potential candidates is whether they're able to self-fund.

"Because if they can't do that first, they probably can't compete," he said. "And that is not a good criteria for the best people serving in office."

Ingram acknowledged that he has managed several races, including Corker's and Haslam's, in which the candidates poured millions of their own money into their bids. But by not taking advantage of the unlimited self-funding rules, "you've placed yourself at a serious disadvantage," he said .

"It's like if steroids were legal in baseball, everybody would take steroids," he said. "And politicians and companies are going to take advantage of the rule to the fullest extent."

Tanner and Ingram agreed that changing the current campaign and redistricting systems will be difficult because it serves incumbents' interests.

"The people responsible for changing the rules are the people benefiting from the rules," Ingram said.