Sen. Ron JohnsonRonald (Ron) Harold JohnsonSunday shows preview: Coronavirus dominates as White House continues to push vaccination effort Overnight Health Care: WHO-backed Covax gets a boost from Moderna Vaccine hesitancy among lawmakers slows return to normalcy on Capitol Hill MORE (R-Wis.) is racing to link former Sen. Russ Feingold to Hillary ClintonHillary Diane Rodham ClintonMcConnell: Taliban could take over Afghanistan by 'the end of the year' Hillary Clinton: There must be a 'global reckoning' with disinformation Pelosi's archbishop calls for Communion to be withheld from public figures supporting abortion rights MORE's email scandal, as Republicans home in on his Democratic challenger's State Department tenure. 

Johnson released a web ad Tuesday asking, "What is Feingold hiding?" It argues the Democrat and the State Department should "follow the law" by releasing emails from when Feingold served as the special envoy for the Great Lakes region of Africa.
“Senator Feingold’s State Department email scandal is just like Hillary Clinton’s — so much so that it can be difficult to tell the two apart,” said Brian Reisinger a spokesman for Johnson's campaign.
He added if the former senator "has nothing to hide and he wasn’t illegally running a shadow campaign while at the State Department, he should demand that the State Department follow the law and release his emails immediately.”
The ad splices national TV news footage on the private email server scandal that has haunted Clinton's Democratic presidential campaign with reports on the GOP-led push to get the State Department to release Feingold's emails before the election. 
Republicans have pounced on the issue after the State Department told the National Republican Senatorial Committee (NRSC) in August that it wouldn't be able to complete its Freedom of Information Act (FOIA) request on Feingold's emails and other details until December. 
Republicans believe the release of the emails will prove that Feingold planned his 2016 Senate campaign from the State Department. 
The Republican Party of Wisconsin filed a complaint with the Office of Special Counsel late last month alleging that Feingold violated the Hatch Act, which restricts how government employees can engage in certain political actives. 
Democrats have brushed off the GOP attacks. Feingold's campaign released a statement from attorney Marc Elias to earlier this month noting the law "does not restrict private conversations between employees and their family, friends, and colleagues. The Republicans' suggestion to the contrary is unfounded." 
Asked about the FOIA request and the GOP push for Feingold's emails earlier this month, Michael Tyler, a spokesman for Feingold, said that "Sen. Johnson's never acted more like a desperate politician." 
"Since he's under fire over his shady $10 million corporate payout he gave himself when he headed off to Washington after spending $9 million out-of-pocket for his campaign, he should stop lobbing up tired partisan attacks and come clean with Wisconsinites," he added. 
The campaign has also touted Feingold's support for strengthening FOIA laws and noted government agencies frequently have a monthslong FOIA backlog. 
Democrats have hounded Johnson over $10 million in compensation that Johnson received from PACUR, his former company. Johnson and his campaign have dismissed the allegations, noting that he disclosed the backpay as part of a Senate financial disclosure form. 
Feingold and Johnson are facing off in a rematch election, with Democrats viewing Wisconsin as a prime pickup opportunity. Feingold is leading by nearly 10 percentage points, according to a RealClearPolitics average polling. 
Democrats need to net five seats — or four if they also retain the White House — to win back the Senate majority.