WASHINGTON (AP) — Republican Sen. Susan Collins, a key vote on President Donald Trump’s pick for the Supreme Court, said Sunday she would oppose any nominee she believed would overturn the landmark Roe v. Wade decision that legalized abortion.

The White House is focusing on five to seven potential candidates to fill the vacancy of retiring Justice Anthony Kennedy, a swing vote on the court. The Maine senator said she would only back a judge who would show respect for settled law such as the 45-year-old Roe decision, which has long been anathema to conservatives.

“I would not support a nominee who demonstrated hostility to Roe v. Wade because that would mean to me that their judicial philosophy did not include a respect for established decisions, established law,” Collins said.

Such a judge, she said, “would not be acceptable to me because that would indicate an activist agenda.”

Trump spent the weekend at his New Jersey golf club conferring with his advisers, including White House counsel Don McGahn, as he considers his options to fill the vacancy that might make precedent-shattering court decisions on abortion, health care, gay marriage and other issues.

The president told reporters Friday that he was homing in on up to seven candidates, including two women, and would announce his choice on July 9.