Outside Money Drives a Deluge of Political Ads

An explosion of spending on political advertising on television — set to break $2 billion in congressional races, with overall spots up nearly 70 percent since the 2010 midterm election — is accelerating the rise of moneyed interests and wresting control from the candidates’ own efforts to reach voters.

In the first full midterm cycle where outside groups have developed a sophisticated infrastructure, the consequences are already becoming apparent: a harshly negative tone dictated by the groups and a nearly nonstop campaign season that could cause voters to tune out...