Conservative Justice Bette Kavanaugh has been approved by US senate and will serve as a lifetime judge in the US top Court.
The highest court in the US is often the final word on highly contentious laws, disputes between states and the federal government, and final appeals to stay executions.
It hears fewer than 100 cases a year and the key announcements are made in June.
Each of the nine justices serve a lifetime appointment after being nominated by the president and approved by the Senate.
Kavanaugh was nominated by President Donald Trump and now has been approved by senate who backed his nomination by 50 votes to 48.
While a majority of Supreme Court cases do not break on ideological lines, there are conservative and liberal wings.
Key cases have been decided on 5-4 votes.
With Justice Kennedy’s departure, the court was arguably divided four-four.
Now after confirmation of Justice Bett Kavanaugh the Court returns to a narrow conservative majority.
Usually, cases are brought to the court after they are appealed from a series of lower courts, although in time-sensitive cases, lawyers can petition for a hearing.
The court’s opinions can also create precedents, directing other judges to follow their interpretation in similar cases.
In recent years, the court has expanded gay marriage to all 50 states, allowed for President Donald Trump’s travel ban to be put in place and delayed a US plan to cut carbon emissions while appeals went forward.
Occasionally, the Supreme Court will revisit an issue in a new case and change their own precedent, a move anti-abortion activists hope will come to pass with a new conservative justice.
The court makes many of its big decisions in June.
This year it ruled on contentious issues such as the Trump travel ban, trade union fees and gerrymandering.
Despite being appointed by Ronald Reagan, Justice Kennedy sided with both the conservative and liberal justices on major cases.
He was a moderate on social issues, notably backing gay marriage.
Now Kavanaugh a more conservative judge has replaced him, it is more likely that anti-abortion advocates could push to get that issue under consideration by the top US court.
Does the US top court matter globally?
US research suggests that the influence of the Supreme Court abroad has diminished over the past two decades, as court systems elsewhere in the world develop and US influence in general wanes.
Fewer courts internationally cite US Supreme Court opinions, increasingly citing the European Court of Human Rights and other national supreme courts.
In 2016 a Supreme Court decision on emissions from coal-fired power plants on US soil threatened the Paris Climate Agreement, but enough other countries ratified the treaty for it to come into force.
Donald Trump’s controversial travel ban, which affects Middle East countries designated as terror-prone, was cemented this week by the Supreme Court, with the outcome affecting millions internationally.
And back in 2000, the Supreme Court decided the outcome of the presidential election between George W Bush and Al Gore – a decision which more recent history shows still has a significant impact around the world.
The court could in theory be asked to rule on legal challenges to international trade agreements, such as the controversial Trans-Pacific Partnership, although TPP was revoked by Mr Trump using an executive order.