By Jess Bravin and Brent Kendall
A sharply divided Supreme Court on Monday ruled unconstitutional an Arizona campaign-finance law that offered extra public funding to state political candidates who faced well-heeled opponents.
The court's conservative majority, in an opinion by Chief Justice John Roberts, added to a string of 5-4 votes invalidating campaign finance regulations, including last year's landmark Citizens United decision that struck down decades-old laws limiting corporate and union political spending.