As Illinois Comptroller Susana Mendoza took the oath of office — her hand on Judy Baar Topinka’s family Bible — the Democrat who dubbed herself an independent fiscal watchdog throughout the campaign threw herself into one of the most chaotic times in the state’s history.

“I ask you to please bear with me. This is going to be tough. Keep me in your prayers even, as I take on what will be the most challenging experience of my lifetime,” Mendoza said after her swearing-in ceremony at the Capitol in Springfield.

The state has more than 126,000 unpaid bills, totaling more than $10.3 billion. And it’s still paying invoices back from June.

From a fresh lawsuit filed about legislator pay, to preparing for the worst without a deal on a full-year budget, an emotional and grateful Mendoza said she would work to prioritize the most vulnerable before any other — volunteering that she won’t pay lawmakers unless a court instructs her to do so.

“I hope my former colleagues in the Legislature will understand my decision to continue to prioritize the most vulnerable people in our state over payments to legislators,” Mendoza said. “I, too, will be putting my paycheck in the same queue as everybody else’s, because in these times of fiscal crisis, these must be times of shared sacrifice, and we must prioritize the most vulnerable first.”

Mendoza defeated Republican Leslie Munger — Gov. Bruce Rauner’s appointed pick — following Topinka’s death in 2014. Mendoza’s ties to Illinois House Speaker Michael Madigan, and Munger’s ties to Rauner played a large role in their campaign.

As comptroller, Mendoza becomes the state’s check writer — with limited discretion in who gets paid. Mendoza said her office would have a say in about “10 percent” of the budget, saying 90 percent is already prioritized via court orders and consent decrees. She said she’d work to advocate and be a voice for prioritizing the most vulnerable, in areas she can’t actively control.

And she had her own ideas about how to reach a balanced budget, saying rank-and-file lawmakers should have a say in enacting a list of priorities, and that leaders should work on figuring out what revenues are needed and where to cut. She argued against tying reforms to the budget, which Republican leaders and Rauner have been pushing for years.

“This should not be held hostage to other non-budgetary related items, things like term limits. They can stand on their own. Vote for those on their own,” Mendoza said. “Why should that be tied to the budget when people are being crippled across the state of Illinois? So I think that there is something to be said about encouraging and really putting pressure on the Legislature to get a budget passed.”

It was Munger in May, while seeking re-election, who said she’d delay legislator paychecks, citing the unfairness of paying them over cash-strapped social service agencies, other non-profits and small businesses.

And Republicans saw the filing of the suit on Friday, Munger’s last day, as a low blow. Her name is listed as a the sole defendant in the suit. Democratic legislators who filed the suit had political overtones, saying the wealthy Munger and Rauner were holding pay for political leverage over the budget.

Rauner on Monday tried to keep pressure on Mendoza — on Day One — to ardently fight against the suit, which was filed by a group of Democratic legislators who rely solely on their state paychecks.

“I hope that she’ll speak out about it every day. I hope that she will get her own special counsel and not purely count on Attorney General Lisa Madigan to fight the lawsuit,” Rauner said.

He also urged the plaintiffs to drop the suit, calling it “insulting to taxpayers” and to human services recipients.

Mendoza’s office responded to calls for an independent counsel in a statement, citing her office’s independence from the governor’s office.

“We appreciate the governor’s advice but as an independent constitutional office, we’ll explore our best legal options on this case and any others,” Mendoza spokesman Abdon Pallasch said.

The Illinois Attorney General’s office, however, on Monday said it’s reviewing the lawsuit and plans to represent the comptroller’s office.