Lt. Gov. Mike Stack III, the scion of an entrenched Northeast Philadelphia political family whose first term in statewide elected office has been marked by controversy and a rift with his boss, kicked off his reelection campaign Tuesday.

"It's not a secret this year has been difficult for my family and me, but we're emerging stronger and healthier," Stack said at the announcement at City Hall.

He did so flanked by U.S. Rep. Bob Brady, head of the Democratic City Committee, labor leaders, and what his campaign called "reformers and activists on the front lines of the fight for restorative justice and the well being of Pennsylvania's veterans."

But despite promises of such broad support, his race to keep his seat, one that typically flies under the radar, is shaping up to be among the most intriguing if not compelling primary campaigns in Pennsylvania in 2018.

The incumbent already has a slate of challengers, including John Fetterman, a small-town mayor and populist who elevated his profile with an unsuccessful campaign for U.S. Senate last year. And one person whose backing Stack has not secured is his boss, Gov. Wolf.

During a nearly 45-minute news conference Tuesday, as a parade of elected officials and other supporters vouched for Stack's progressive principles, Wolf's name barely came up.

Stack and his wife, Tonya Stack, came under scrutiny last spring after Wolf directed his Inspector General to launch an inquiry into whether they verbally abused the state employees who work for them. In Pennsylvania, lieutenant governors and their families traditionally receive State Police protection and live in a residence outside Harrisburg that is staffed with a cook, housekeeper, groundskeepers and others.

Sources have told The Inquirer and Daily News that the Democratic governor warned the Stacks to change their behavior, and when they didn't, he asked Inspector General Bruce Beemer's office to investigate the matter and write up a report.

The governor also took the extraordinary step of stripping the Stacks of their State Police protection, and scaled back staffing at the residence as the investigation unfolded.

In a public apology after news of the report became public in April, Stack acknowledged that anger and frustration had led at times to what he called "a Stack moment."  He later took it a step further, calling his and his wife's behavior a symptom "of a larger problem." He did not elaborate.

Responding to media requests, Stack's office later issued a statement saying that Tonya Stack, 47, had entered a treatment facility to receive assistance in coping with a mental health problem.

Since that time, Wolf's office has been silent about the status of the inspector's report. Though Wolf had once signaled he might publicly release it, spokesman J.J. Abbott could not say Tuesday if the governor still intends to.

"This is still going through the legal process," Abbott said. He did not elaborate.

Stack said Tuesday that he had not seen a final copy of the inspector general's report. He added he hadn't spoken with the inspector general's office "for months." Wolf hasn't brought it up either, he said.

"I think it's a private family health issue," Stack told reporters. "And I really don't think it's appropriate to talk about it publicly."

"We appreciate the love and support that we've received," he added.

Wolf and Stack have never been close. Though under state rules, the two men ran as a ticket in the 2014 general election, Wolf didn't hand-select Stack as his running mate. And since taking office in 2015, the two have rarely appeared together in public, let alone, worked together on high-profile policy issues.

Stack, whose grandfather was a congressman and father a Democratic ward leader, was a longtime state senator before winning statewide office in 2014 as Wolf's second-in-command. In the Capitol, he presides over the state Senate, dressed in crisp suits and often injecting lounge-like commentary into the normally staid workings of the chamber.

Fetterman, who supported Bernie Sanders over Hillary Clinton, this month won his fourth term as mayor of Braddock, a struggling industrial town near Pittsburgh. At 6-foot-8, Fetterman, who wears all-black short-sleeve shirts and shorts, looks like he could have worked at one of Braddock's old steel mills. He earned a masters in public policy from Harvard.

"I feel very comfortable about the competition and the race," Stack said.

Early Tuesday morning, Fetterman's campaign announced it had raised $100,000 in the last seven days. His campaign described that as evidence of "a wave of enthusiastic support" that showed "Pennsylvanians are hungry for a genuine, progressive candidate like John Fetterman."

Fetterman isn't the only one eyeing Stack's job. Other announced candidates are Aryanna Berringer, an IT project manager from Westmoreland County; Chester County Commissioner Kathi Cozzone; and Lancaster County Commissioner Craig Lehman. Democratic state Rep. Madeleine Dean of Montgomery County has said she is seriously considering a run.

On the Republican side, Main Line Republican Jeff Bartos recently announced his intention to run for lieutenant governor as part of a team with Sen. Scott Wagner (R., York), who is seeking the Republican nomination to run for governor against Wolf.