Attorneys for the state of Rhode Island will ask a judge to dismiss a legal challenge to the state's landmark pension overhaul filed by public-sector unions.

The hearing in Judge Sarah Taft-Carter's Providence courtroom on Friday is the highest profile one yet in the legal dispute over the year-old pension law. Unions argue the changes to state retirement benefits are unconstitutional and unfair.

State leaders insist that without the changes, ever-escalating pension costs would swamp state finances. They say the pension law — which passed overwhelmingly in 2011 — was carefully crafted to withstand legal scrutiny.

The litigation could have far-reaching implications as states around the country seek to rein in pension costs. Collectively, states face a $1.4 trillion gap between what they've promised workers and what they've set aside to pay for those benefits.

Rhode Island has attracted a high-profile defender: New York attorney David Boies has asked to join the legal team defending the law because of what he has said are the case's implications for other governments dealing with their own pension problems.