What Can $3.7 Billion Buy? How About 2,969,370 Campaign Ads

Two new reports find that the House and Senate elections will cost about $3.7 billion — up just slightly from the past two election cycles — with outside groups buying their largest share yet of the television advertising.

The nonpartisan Center for Responsive Politics, in Washington, says candidates and political parties are spending less this cycle, while outside groups are spending more. Its report does not include spending that outside groups don't report to the Federal Election Commission. One prominent example is a months-long TV campaign against vulnerable Democratic senators...