Supreme Court Justice Anthony Kennedy announced his retirement Wednesday, giving President Donald Trump the chance to cement conservative control of the high court.

The 81-year-old Kennedy said in a statement he is stepping down after more than 30 years on the court. A Republican appointee, he has held the key vote on such high-profile issues as abortion, affirmative action, gay rights, guns, campaign finance and voting rights.

Kennedy said he has informed his colleagues and Trump of his plans, and that his retirement will take effect at the end of July.

Without him, the court will be split between four liberal justices who were appointed by Democratic presidents and four conservatives who were named by Republicans. Trump’s nominee is likely to give the conservatives a solid majority and will face a Senate process in which Republicans hold the slimmest majority, but Democrats can’t delay confirmation.

Trump’s first high court nominee, Justice Neil Gorsuch, was confirmed in April 2017. If past practice is any indication, Trump will name a nominee within weeks, setting in motion a process that could allow confirmation of a new justice by early August. Trump already has a list of 25 candidates — 24 judges and Utah Sen. Mike Lee — from which the White House has previously said he would choose a nominee.

Prominent on that list are Judges Thomas Hardiman of Pennsylvania and William Pryor of Alabama, seriously considered for the seat eventually filled by Justice Neil Gorsuch, and Judge Brett Kavanaugh, who serves on the federal appeals court in Washington, DC.

Kavanaugh is a longtime Washington insider, having served as a law clerk to Kennedy and then as a key member of independent counsel Kenneth Starr’s team that produced the report that served as the basis for President Bill Clinton’s impeachment. In October, Kavanaugh dissented when his court ruled that an undocumented teen in federal custody should be able to obtain an abortion immediately.

Abortion is likely to be one of the flash points in the nomination fight. Kennedy has mainly supported abortion rights in his time on the court, and Trump has made clear he would try to choose justices who want to overturn the landmark abortion rights case of Roe v. Wade. Such a dramatic step may not be immediately likely, but a more conservative court might be more willing to sustain abortion restrictions.

Interest groups across the political spectrum are expected to mobilize to support and fight the nomination because it is so likely to push the court to the right.