A once-prominent and powerful Democratic state senator in Wisconsin has passed away.

Former State Sen. Tim Cullen, who served for several years as the Democratic Majority Leader in that chamber in the 1980s, died this week at the age of 80, Wisconsin's Channel3000 reported.

His death prompted an outpouring of condolences and tributes from friends and former colleagues who'd worked with the popular legislator in decades past.

Served as Senate Majority Leader

According to WCLO News, Cullen's family revealed that the former state senator from Janesville passed away on Monday after being hospitalized in Madison for a heart condition.

Cullen was first elected to the Wisconsin State Senate in 1974, became the majority leader in 1982, and served until 1987, when he resigned to serve for a year as secretary of the state's Department of Health and Social Services under then-Republican Gov. Tommy Thompson, after which he left government service for roughly two decades to pursue various opportunities and interests in the private sector.

That included becoming a regional vice president for Blue Cross Blue Shield, as well as an author and activist who launched a mentoring program for high school students interested in politics and government, among other things.

Fell victim to the partisanship he once decried

Per WCLO, Cullen returned to the legislature after he was re-elected as a state senator again in 2010 but ultimately retired from politics in 2015, citing increased partisanship as the reason.

Indeed, once known as a centrist Democrat who combined "a businessperson’s pragmatism along with progressive ideas," he was often praised by Democrats and Republicans alike for his work to bring both sides together in search of compromise solutions.

However, Cullen himself became more partisan during his second stint in office and helped lead the leftist opposition to then-Republican Gov. Scott Walker's government reforms.

That included being part of the group of Wisconsin lawmakers who absconded to the neighboring state of Illinois for several weeks in a desperate bid to deny Walker the Senate quorum needed to pass some of his conservative policies.

Mourned by Gov. Evers

According to WFRV, Wisconsin's Democratic Gov. Tony Evers issued a statement to mark the death of former State Sen. Cullen, who he described as "a dedicated public servant who devoted much of his life to good governance and improving the state that raised him."

"Sen. Cullen always fought for working families, gave back to and supported kids in the Janesville area, and advocated fiercely for nonpartisan redistricting and access to the ballot box during both his time in the Wisconsin State Senate and beyond it," the governor continued. "He spent much of his life working to end partisan gerrymandering and fighting for Wisconsin to have fair maps at long last."

"There is no doubt our state is better off because of Sen. Cullen and his service. Kathy and I extend our deepest condolences to his family, colleagues, and all those who knew him," Evers added.

Prior to joining the state senate, Cullen first served on the Janesville City Council and the Janesville Public School District board, while after his public service concluded, he was chairman of an ostensibly nonpartisan group known as Common Cause Wisconsin that advocated for good government.