Maine Sen. Susan Collins sided with Democrats on Thursday to oppose one of President Trump’s controversial selections for the federal bench, although Republicans still had enough votes to approve the judicial nominee.

Collins was the only Republican to vote against ending the filibuster on Wendy Vitter, who has been nominated to serve as a U.S. District Court judge in the Eastern District of Louisiana. The 51-45 vote Wednesday to end debate – with all Democrats and Collins opposed – allowed the Senate to take a final vote on Vitter’s nomination.

She was approved on a vote of 52-45 shortly after noon Thursday, with Collins voting in opposition.

Maine Sen. Angus King, an independent, also voted to oppose Vitter.

A number of progressive and civil rights groups – including the NAACP, the Human Rights Campaign and Planned Parenthood – have strongly opposed Vitter, who is the wife of former Republican Sen. David Vitter of Louisiana. For instance, the NAACP criticized the nominee for failing during her Senate confirmation hearing to explicitly support the landmark 1954 Supreme Court decision in Brown v. Board of Education that ended racial segregation in schools. She is also viewed as strongly anti-abortion.

Collins cited those two issues in opposing the nominee.

“At the Judiciary Committee hearing, her answers to a question on the landmark case of Brown v. Board of Education as well as the inquiries on her advancing discredited assertions about the impact of contraception and abortion on the incidence of cancer and domestic violence lead me to conclude that she is not well-suited to serve on the federal bench,” Collins said in a statement Thursday.

“Let me be clear that my decision is not based on Mrs. Vitter’s personal views on abortion and contraception which she has every right to hold,” Collins said. “Rather, I question whether she could put aside her personal views given that she encouraged participants at a seminar to urge their doctors to have in their waiting rooms a pamphlet that linked contraception and abortion to cancer and an increased risk of domestic violence. These harmful claims have been widely discredited by the medical community.”

Thursday’s vote came at a time of feverish national debate over abortion.

Although abortion is a perennial issue, the political debate has erupted in recent months due, in large part, to abortion opponents’ desire to stack the courts with more conservative judges under Trump. Republican lawmakers and governors in Georgia, Alabama, Missouri and other states are pursuing severe restrictions on abortion in hopes of getting the issue before the Supreme Court.

In Maine, meanwhile, lawmakers recently passed a measure to broaden access to abortion by requiring the state to pay for the procedure under its Medicaid program. Another bill moving forward would authorize nurse practitioners and other health care providers to perform abortions.

Collins is being targeted by both sides.

The Maine senator is one of the few Republicans in Congress who supports preserving a woman’s right to have an abortion. Yet she infuriated abortion rights groups last year when she voted to confirm Supreme Court Justice Brett Kavanaugh, who abortion opponents hope could cast key votes in whittling away at or even overturning the Roe v. Wade case that legalized abortion nationwide.

Collins, who is up for reelection in 2020, has been under intense scrutiny from abortion rights and progressive groups ever since the Kavanaugh vote. Groups also have criticized Collins for voting to support other judicial nominees whom they view as anti-abortion, including voting Tuesday to support the appointment of Michael Truncale to serve on the U.S. District Court in the Eastern District of Texas.

Earlier this week, the liberal political action group Demand Justice Initiative threatened to run online ads in Maine targeting Collins and focusing on Vitter’s anti-abortion record.

“The recent laws passed in Georgia and Alabama prove there is an all-out assault on abortion rights underway in this country, and Senator Collins needs to choose a side,” the group’s executive director, Brian Fallon, said in a statement. “When Senator Collins supports so many of Trump’s anti-abortion judges, it is reasonable for Mainers to conclude she’s not living up to her promises about protecting reproductive rights.”