The US Supreme Court today struck down a Montana campaign finance law that would have allowed states to curb the impact of the court's earlier Citizens United ruling. In a 5-4 vote along the court's usual ideological divide, the court issued a summary reversal, ignoring liberal justices' calls for a full hearing on the case, which they had hoped would allow the court to reconsider and perhaps overturn United in light of the massive spending that's occurred since, the AP reports.