Sen. Susan Collins of Maine, long branded a “moderate” Republican but better known to conservatives as a serial Trump obstructionist, is staring down the toughest reelection battle of her 30-year political career.

Collins, now seeking a sixth term in the U.S. Senate, will face multiple challengers in the 2026 Republican primary — including candidates openly supportive of President Donald J. Trump and the America First agenda that Collins has repeatedly undermined.

According to Maine Morning Star, Collins is already facing at least two challengers within her own party: Carmen Calabrese of Kennebunkport and Daniel Smeriglio of Frenchville. A third candidate, Phillip Rench of Waterboro, is also in the race as an Independent, though his policy positions are clearly to the right of Collins on several core issues.

And more challengers could still enter the fray.

Democrats are also gearing up to flip the seat, sensing weakness in Collins’ centrist base and long history of frustrating the Republican grassroots. The declared Democratic candidates so far include Jordan Wood, a former Capitol Hill staffer with ties to progressive Rep. Katie Porter (D-CA), and Natasha Alcala, a Navy veteran and fashion designer from California with degrees in criminal justice and international relations.

Collins is attempting to fend off critics by touting her seniority and her influence on one of the Senate’s most powerful appropriations committees. She claims that this leverage allowed her to secure over $1 billion in federal earmarks for projects throughout Maine — an argument she says proves her effectiveness.

“By climbing that ladder in the last three years I have been able to secure more than a billion dollars for hundreds of projects in communities across our state,” Collins told reporters. “That would not have happened without the seniority that I have.”

But her opponents say that being an effective spender of taxpayer dollars doesn’t excuse her repeated betrayals of conservative principles — or her opposition to President Trump’s agenda during his first term.

Calabrese, who is running a grassroots campaign from Kennebunkport, pushed back on Collins’ claims of fiscal stewardship.

“You can’t argue with that. But I look at it as well, I thank you for bringing it, but you’re also spending my money. It’s my tax dollars,” Calabrese said, adding that Maine would be better served if Collins aligned herself more closely with Trump’s pro-growth, anti-globalist policies.

“If you agree more with some of the stances that he has, maybe you’ll do better,” Calabrese added.

Independent candidate Phillip Rench echoed the concern — but took it even further, criticizing Maine’s reliance on Washington and proposing bold reforms to reverse the state’s economic decline.

“What we need to do as a state is become less dependent on federal dollars,” Rench said, promising to rebuild Maine’s economic backbone through education reform and industrial revitalization.

A former space industry professional, Rench returned to Maine and now serves on the board of the Maine Space Corporation. He wants to reverse the state’s “brain drain” by offering dual pathways in education — college and skilled trades — and hopes to build out new sectors, including domestic food production, dimensional lumber reserves, and aerospace infrastructure.

While the establishment media continues to describe Collins as a “moderate,” many on the right view her as a holdover from the Bush-era GOP — a relic in a party that has moved on under Trump’s unapologetic America First movement. Her consistent bucking of President Trump’s policies, including on border security, Supreme Court confirmations, and spending reforms, has made her a perennial target among conservative voters who feel ignored and betrayed.

With strong primary challengers now emerging and grassroots energy rising, Collins may finally face the reckoning many in her own party believe is long overdue.