BRISTOL, R.I. — Retired U.S. Supreme Court Justice Sandra Day O’Connor said the nation is in trouble in the area of campaign finance and told a group of law students that “careful thinking” is needed after a 2010 Citizens United decision by the high court.

The decision allowed wealthy individuals and corporations to spend freely to influence elections.

“Citizens United produced a decision that, over the years, is going to cause lots of issues for the public to resolve,” O’Connor said at Roger Williams University School of Law on Wednesday, a day after the high court heard another campaign finance case in which a wealthy donor is seeking to lift overall caps on individual donations during an election cycle. The case is the court’s first major campaign finance case since the 2010 ruling.

“I think it may have caused more problems than answers given,” she said of the 2010 decision. “I don’t know what we’re going to do with the problems raised by Citizens United.”

O’Connor, 83, was appointed to the court in 1981 by President Ronald Reagan. While a justice, she often voted to uphold campaign limits. She retired in 2006.

She appeared in conversation with Judge Bruce Selya of the 1st U.S. Circuit Court of Appeals, then took several questions from students.

O’Connor said she had not read about the case heard this week by the high court, but Selya informed her of the broad outlines.

“That’ll put them to the test again,” she responded. “We’re in a bit of trouble in this whole area, I think. It needs attention and careful thinking as to how we can go from here. Citizens United opened a lot of issues.”

In the case heard Tuesday, Republican activist Shaun McCutcheon, the Republican Party and Senate Republican leader Mitch McConnell want the court to overturn the overall limits on what contributors may give in a two-year federal election cycle.

The total is $123,200, including a separate $48,600 cap on contributions to candidates, for 2013 and 2014.