The Supreme Court reaffirmed on Monday the right of corporations to make independent  political expenditures, summarily overturning a 100-year-old Montana  state law that barred companies from such political activity.

The  justices ruled in an unsigned opinion that Montana's law was in conflict  with the court's 2010 Citizens United decision, which shifted the  campaign finance landscape, opening the door to the huge political  expenditures that have been shaping this year's presidential race. The  decision was 5-4, split along ideological lines.

Despite the  Citizens United decision, the Montana Supreme Court had refused to  strike down the state's ban on election spending by corporations. Its  judges cited Montana's history of "copper kings" who bribed legislators.  Advocates of campaign finance reform had hoped that the current wave of  election-related spending would help make their case for the need to  reconsider Citizens United.

Advocates for stricter campaign finance  regulations said they will continue their fight for tougher laws in  Congress and the courts.

<span style="color: #000000;">Montana Attorney General Steve Bullock says the U.S. Supreme Court decision to strike down Montana's restrictions on corporate political spending was politically motivated. Gov. Brian Schweitzer was even blunter, saying the Supreme Court is now endorsing "dirty, secret, corporate, foreign money." The high court overturned the state campaign finance restrictions in a case that  piggybacked the 2010 Citizens United decision that allowed corporations  to spend freely to influence elections.</span>