All eyes on Roberts ahead of Supreme Court's abortion ruling

Chief Justice John Roberts is under the microscope as the Supreme Court prepares to issue its first major ruling on abortion rights in the Trump era, which will give the clearest indication yet of the court’s willingness to revisit protections that were first granted in Roe v. Wade.

The tie-breaking vote may rest with Roberts, and the case stands to test his role as the court’s new ideological center as well as his allegiance to past rulings.

A decision could come as early as Monday, following a blockbuster week at the court. Roberts joined narrow majorities last week to extend civil rights protections to gay and transgender people and block the Trump administration’s plan to end a deportation shield for young undocumented immigrants under the Deferred Action for Childhood Arrivals (DACA) policy.

But the abortion rights case differs from the others in a key respect. Whereas the LGBT and DACA disputes asked the justices to interpret the meaning of federal law, the Louisiana case asks the justices to weigh their own past rulings on abortion.