Washington(CNN) A government investigation concluded that the United States Postal Service "improperly coordinated" with a postal workers union that supported Hillary Clinton's campaign.
The investigation, as documented in a report from the Office of Special Counsel, said the USPS granted employees union leave time off, at the request of the union, to do political activity -- which OSC concluded was a "systematic violation" of a law regarding the political activity of federal employees.
The report said the practice was longstanding, perhaps ranging as far back as the 1990s.
The report came in response to a request from Wisconsin Republican Sen. Ron Johnson, who chairs a Senate committee that held a hearing Wednesday on the matter and asked representatives of government watchdogs why it went on so long. William Siemer, the acting deputy inspector general of the USPS's inspector general's office, indicated it was a case of institutional inertia.
"It seemed that it was adopted just as a practice where nobody was really looking at it through the lens of is this appropriate or not," Siemer said.
A message left with the Clinton campaign Wednesday afternoon was not immediately returned.
OSC's report said the USPS's actions during the 2016 campaign violated the Hatch Act, a 1939 law intended to keep federal employees from directly supporting candidates. The report said OSC will not seek individual punishments for violation of the law but said USPS needed to take corrective measures, including no longer considering political activity as a reason for official union leave and implementing a "'hands off' approach to a union's political activity."
The issue in question, which Johnson said was brought to his attention by Timm Kopp, a letter carrier and constituent who spoke at the hearing, concerned USPS's coordination with the National Association of Letter Carriers for employees to take leave to participate in an AFL-CIO political effort to get Clinton elected and help "other pro-worker candidates across the country" by getting workers to do things like canvass door-to-door and man a phonebank.
According to the report, the union would provide a list of USPS employees to USPS, asking they be put on unpaid leave to participate in the political effort. Then the USPS management would disperse the lists, which were viewed lower down as "directives," to give the letter carriers time off, including telling local supervisors to do so over concerns it would affect postal operations. The union would pay the employees out of its own political fund during their time off.
Kopp said he and others had to work overtime to keep operations going while others were off on political work, and he said he tried and failed to raise concerns through various channels before getting through at this level.
In his statement at Wednesday's hearing, Johnson said the total scope of the 2016 effort seemed relatively small at a total of 97 employees getting time off, but the senator warned of "unquantified consequences" from operational concerns to unfairness for employees who weren't in the union or wanted to support different candidates from their union.
Missouri Sen. Claire McCaskill, the top Democrat on the committee, said she found the apparent length of the Hatch Act violation "shocking" but said the USPS' response to the report was encouraging.
Postmaster General Megan Brennan appeared before the committee to address the conclusions of the report to Congress. She said after receiving the results of the investigation last Friday, the USPS "fully accepts and will fully implement" the OSC's recommendations to avoid future Hatch Act violations.