By custom, lieutenant governors are supposed to keep a low profile.
The political intrigue surrounding Pennsylvania Lt. Gov. Mike Stack, however, could rival a House of Cards episode.
The state's inspector general is investigating complaints that Stack, a longtime political player from Philadelphia, and his wife, Tonya, verbally abused members of their state police security detail and household staff at their official residence near Harrisburg.
What makes the probe particularly notable is the driving force behind it. According to two sources familiar with the matter, Gov. Wolf initiated the scrutiny on Stack, who was expected to be his running mate in next year's reelection campaign.
Wolf acted after state troopers and employees at the lieutenant governor's mansion at Fort Indiantown Gap complained that the Stacks often berated them, according to the sources, who spoke on the condition of anonymity because they were not authorized to publicly discuss it. One state employee briefed on the allegations said the Stacks used "extremely graphic, profane language" and had threatened workers with their jobs.
Wolf's spokesman has declined to comment, as did Inspector General Bruce Beemer, who was named to the job last year by Wolf. Stack's office confirmed a review was underway in a two-line statement Monday night. Late Tuesday, Stack's office announced he would hold a news conference Wednesday to address the inquiry.
But the timing and disclosure of the probe – first reported Monday by LNP Media in Lancaster and Harrisburg television station ABC27 – underscored an unspoken but understood political reality in the Capitol.
Friction sometimes arises between governors and their seconds, but there hasn't been such a severe breach in the relationship in Pennsylvania, at least in modern memory. And it comes as Wolf, a first-term Democrat, heads toward a re-election year with middling approval ratings in a state that last year swung Republican in a presidential race for the first time in nearly three decades.
"Typically, no one wins election as governor because of the lieutenant governor," said G. Terry Madonna, the veteran pollster at Franklin and Marshall College in Lancaster. "The question for Wolf is, if there is something to [the probe] ... what does he do in connection with the second term?"
The governor, a 68-year-old York County businessman, didn't choose Stack, 53, a former state senator from Northeast Philadelphia, as his running mate in 2014. Democratic voters did. Candidates for governor and lieutenant governor run separately in party primaries and then as pairs in the general election.
Stack grew up as the son of a ward leader. He served in the Army National Guard as a lawyer and was elected to the state Senate in 2001, representing the Fifth District until he took over as lieutenant governor. The district covers much of the Northeast and dips down to include Bridesburg and parts of Port Richmond.
In the 2014 primary, he was the only Philadelphian on the ballot for lieutenant governor, an advantage because candidates' home counties are listed with their names. Stack beat four other Democratic contenders with 48 percent of the vote.
When in Harrisburg, he and his wife live in a 2,500-square-foot fieldstone house on the grounds of the historic fort, home of the Pennsylvania National Guard. It has a swimming pool and a five-car garage, with a staff of two state employees who manage the property and cook. The lieutenant governor collects a $162,373 salary and a state trooper detail escorts him and his wife.
Late Monday, Stack's chief of staff, Matt Franchak, issued a terse statement acknowledging "a letter from the inspector general in regards to staffing issues." He said the office would have no further details or comment and repeated that stance Tuesday.
It is unclear if the Inspector General's Office will issue a public report. The office is not obligated to disclose its findings, but sometimes does. It doesn't prosecute cases but can refer allegations of government waste or fraud to other law enforcement agencies.
Earlier this year, for example, the Inspector General's Office released the results of an investigation documenting cheating and other problems at the state police academy.
Stack's recent political history has been marked with controversy and what appears to be an inability to let go.
He told stunned political players gathered at the Philadelphia Democratic City Committee's pre-general election party in October 2014 that he was considering maintaining a role as "super-senator" if he was elected lieutenant governor. Stack suggested he could keep his Senate seat while serving in the new post.
That came as news to his running mate. Wolf shot down the idea.
In March 2016, Stack unexpectedly stepped down as the Democratic leader of Northeast Philadelphia's 58th Ward. He backed a committeeman, Mike Kates, to succeed him in the party post. But then Kates threw his support to a state Senate candidate Stack opposed in the race for his seat. The lieutenant governor mounted a recall effort and soon took back control of the ward.
Last year, the lieutenant governor requested language in a draft of the state budget authorizing state police who drive him and other "dignitaries" to use flashing lights and sirens to clear traffic. Current law allows such warnings only in emergencies. Wolf administration officials asked lawmakers to strike the provision.
In 2015, Tonya Stack's temper made headlines after an altercation with State Rep. Kevin Boyle (D., Phila.). He accused her of giving him the finger and dumping a soda on him at a charity event.
Stack is rarely seen in public with Wolf, a pattern that began during their campaign. By contrast, Republican Gov. Tom Corbett gave significant political and policy assignments to Lt. Gov. Jim Cawley. As lieutenant governor, Stack's duties include presiding over the state Senate and heading the Board of Pardons.
Staff writer Chris Brennan contributed to this article.