Former Sen. Russ Feingold has pledged to make college more affordable but Wisconsin Republicans hope to spoil his political comeback by pointing out all the money he has made from academia.

"Sen. Feingold can't have it both ways, and his record places him firmly on the wrong side of students, said Pat Garrett, spokesman for the Wisconsin Republican Party. "While Feingold talks about making college affordable, he hypocritically spent years cashing in— taking in hundreds of thousands of dollars in speaking fees and salaries."

Garrett was referring to Feingold's six-figure salary at Stanford University and honoraria collected from various universities for campus visits listed in his personal financial disclosure forms.

A search of those records dating back to 2013 show he collectively received $450,000 between 2012-15 from 17 different schools, the lion's share coming from Stanford, where he was on staff.

"I consider the issue of student loans and student debt to be one of the most important," Feingold tweeted on Friday.

Feingold is in a grudge match with Republican Sen. Ron Johnson, who unseated the three-term lawmaker in 2010.

"Sen. Johnson and his allies don't seem to understand that this is about the kids of this state, not Sen. Johnson and his corporate backers," Feingold campaign spokesman Michael Tyler responded. "Sen. Johnson's so extreme that he calls student loans 'free money' and would do away with all federal student loans."

Johnson has denied that charge.

"Saying that I only want wealthy kids going to college, nothing could be further from the truth," Johnson told the Milwaukee Journal-Sentinel Thursday.

Tyler blasted Johnson for referring to a "higher-education cartel" comprising "federal student loan program, the accreditation agencies and higher education," in the same interview.

"Just yesterday, Sen. Johnson went out of his way to disparage the dream of higher education as a 'cartel' and defend his out-of-touch policies to keep college financially out of reach for kids from middle-class and working families," Tyler shot back. "The true cartel Wisconsinites face is Sen. Johnson's blind allegiance to Donald Trump and corporate CEOs who want him to stay in Washington for another six years to protect their interests."

Trying to turn Feingold's positives into negatives has been a key strategy of Johnson's campaign.

Johnson has accused Feingold, whose name was once synonymous with campaign finance reform, for reneging on his pledge to eschew "dark money" and collect the bulk of his campaign donations from within the Badger State.

Johnson's camp claims that "Mr. Clean" Feingold is just like any other politician who accepts the help of third-party groups and special interests.

Similarly, Johnson has sought to turn Feingold's lone dissenting vote against the Patriot Act into a liability, arguing that America would be less safe if the Democrat's view had prevailed.

"The bottom line: Sen. Feingold has broken too many promises and is far too hypocritical to be trusted to look out for anyone but himself," Garrett said.

Feingold leads Johnson in both the polls and fundraising.