WATERVILLE — Gov. Janet Mills expressed growing concern Monday about the Trump administration’s anti-vaccine and pro-tariff policies, among other things, but declined to levy criticism on Sen. Susan Collins, who could potentially be her next political opponent.

As Mills appears to be inching closer to a run for U.S. Senate, she participated in a series of public events in Kennebec County. She was asked during one of those appearances to comment on whether Collins, a Republican and Maine’s senior senator, bears any responsibility for how the second Trump administration is playing out.

While Collins has been critical of Trump’s tariffs and supported efforts to end the national emergency used to justify them, she also voted to confirm Robert F. Kennedy Jr., an anti-vaccine advocate, as health secretary. Last week, Kennedy faced senators in a testy hearing over his decision to limit who can receive a COVID-19 vaccination and to cut off millions of dollars in funding for biomedical research — efforts Collins has pushed back against.

“She’s in a tough position,” Mills said of Collins. “I appreciate everything she is doing.”

Mills made the comments to reporters after attending an event with the Rotary Club of Waterville, where her economic commissioner touted the administration’s economic development efforts.

The governor, nearing the end of her second term, is being recruited by national Democrats to take on Collins, a five-term incumbent who they believe is vulnerable because of her low approval ratings. And Mills is a known quantity with a proven track record of winning statewide races.

Although the governor has said she won’t decide until November, her itinerary Monday could easily have been mistaken for a campaign swing.

She began the day having breakfast at the historic A1 Diner in Gardiner. There, Mills again sent a strong signal that she may run, saying she thinks every day about the “disturbing things going on.”

“I’m thinking about that every day,” Mills told MainePublic, according to audio provided by the governor’s office. “You want to be able to solve problems. And there are a lot of problems.”

“People are anxious to get basic stuff done and so am I,” she added.

After the Rotary event, Mills told reporters that the “state of flux in (the) the public health system,” is of great concern, specifically with vaccines, and lamented that tariffs are driving up the cost of everything from coffee to housing supplies.

“I hear people all over the state saying the price of coffee is going up,” she said. “The price of chocolate is going up. The price of groceries is going up. The price of cars and trucks is going up.”

Mills noted that inflation in housing supplies is coming as the state is experiencing a shortage of affordable housing, which has ripple effects on the state’s workforce, as people seek to move here to work but are unable to find a place to live.

“We can’t afford to lose construction when we’re in a housing situation where we have to keep building and innovating in the housing area so we can keep our workforce and keep our people well-housed,” she said. “But because of tariffs on soft wood lumber, on aluminum and steel, the price of construction has gone up reportedly 10% this summer alone. Those are things people tell me are on their minds as well.”

Former Republican Gov. Paul LePage, who is challenging Rep. Jared Golden in the 2nd Congressional District, also attended the Rotary event. He and Mills, who defeated him in the 2022 governor’s race, briefly said hello.

As Mills considers a Senate run, other Democrats have entered the race, increasing the chances that Mills would have to navigate a lively primary to secure the nomination.

Graham Platner, a veteran and oyster farmer from Sullivan, made a splash when he announced his candidacy last month. He reportedly has raised more than $1 million already and has been endorsed by Sen. Bernie Sanders, D-Vt., who held a Labor Day rally in Portland with Platner that drew 6,500 people to the Cross Insurance Arena.

Maine Beer Co. co-owner Dan Kleban launched his campaign last week, but he would not say whether he would stay in the race if Mills announced.

In all, eight Democrats have filed to run for U.S. Senate so far, including David Costello, of Brunswick, who ran unsuccessfully last year against Sen. Angus King; and Jordan Wood, of Bristol, who served as chief of staff to former Rep. Katie Porter, D-Calif.

Democrats Natasha Alcala, Andrea LaFlamme, Tucker Favreau and Daira Rodriguez have all filed federal campaign finance paperwork for the race, as have Republicans Carmen Calabrese and Daniel Smeriglio, and independent Phillip Rench, a former SpaceX senior engineer.