This Washington Post article provides some interesting data on campaign spending in the last election cycle. The editorial raises some important issues about the transformation that is taking place in our electoral system. The spending on 33 Senate races in 2012 was $259 million. Spending on 33 Senate races in 2014 increased by 32% to $342 million. The rapid growth in campaign spending increases the influence of outside groups that are providing an increasing share of the spending.
Another of the issues is that outside spending exceeded the campaign spending by the political parties in 25% of the Senate races. Moreover, "dark spending" by outside groups, which do not have to disclose their donors, provided 71% of the non-campaign spending for the 10 winners of the 11 competitive Senate races. The 11th race in Louisiana has not been decided.
One of the arguments for the Supreme Court decision that led to the increase in outside spending claimed that it would better inform the public. More people would be allowed to exercise their right to free speech, by voting with their advertising dollars, and the public would consider the sources of the information provided in the ads. The rise in "dark money" funding negates that argument. Transparency has been lost in the funding of political campaigns.