The unlimited, undisclosed flow of corporate money into American elections is a serious threat to government "of the people, by the people and for the people," former Vice President Walter Mondale said Thursday. And, ironically, the first venue in which that threat is being felt is the Republican presidential nominating process, he said.

That's ironic because it was GOP appointees to the U.S. Supreme Court that in the 2010 Citizens United decision opened the floodgates for corporate spending on political speech.

The decision was initially welcomed by many Republicans. But the funding flow it made possible is widely credited for prolonging this year's bruising GOP presidential nomination contest, keeping candidates in the race who, under the old rules barring corporate spending, might have dropped out by now for lack of funds.

"We apparently have a lot of maladjusted billionaires in this country," Mondale quipped. He was apparently alluding to Las Vegas casino mogul Sheldon Adelson, whose donations to Newt Gingrich's campaign are said to exceed $20 million, and Wyoming businessman Foster Friess, who is a major benefactor to Rick Santorum's campaign. Two-thirds of the spending to date in the GOP presidential contest has come from undisclosed corporate donors, Mondale said.

Mondale was speaking to the annual luncheon of the Policy Fellows at the Humphrey School of Public Affairs at the University of Minnesota. Now in its 23rd year, the fellows program was founded by Mondale and former U.S. Ambassador Geri Joseph in 1990 to offer mid-career public affairs leadership training for people pursuing business, government and non-profit careers. Mondale is a popular instructor in the program, and has taught more than 1,000 students since its inception.

The former vice president urged the fellows not to "get down in the dumps" about problems with democracy such as those being created by corporate spending. Only through activism, not passivity and resignation, can hope be sustained and the democracy strengthened, he said.