A newly empowered spate of independent groups helped contribute to the glut, investing millions in their own TV advertising to influence the 2012 contest.
A series of federal court rulings, including the landmark Citizens United Supreme Court decision in 2010, significantly eased campaign finance regulations, freeing corporations and wealthy individuals to spend money to influence politics.
Pro-Romney groups American Crossroads and Americans for Prosperity and pro-Obama groups led by Priorities USA Action eagerly took advantage of the new rules. Collectively, Republican outside groups vastly outnumbered — and outspent — their Democratic counterparts.
But it's not at all clear whether TV ad spending by super PACs and other outside groups was a smart use of their cash.
Television stations, by law, must grant presidential candidates lower ad rates than regular commercial advertisers receive. That discount is not available to the political parties nor the outside groups, forcing them to pay much higher rates in battleground states where ad space is at a premium.
That's in part why Obama aired more spots than did Romney and his super PAC allies. Obama and Democratic-leaning groups spent approximately $460 million on the airwaves, the vast majority coming from the president's campaign. Romney and the Republican groups spent $624 million, more than half of which came from outside groups.
The president's campaign aired about 503,000 ads since June 1, the Wesleyan study found, compared to about 191,000 for Romney. The Republican hopeful was aided by some 270,000 ads from outside groups supporting his candidacy. While there is no question the outside groups helped bring Romney to parity with Obama on the airwaves, the president's campaign, by taking advantage of the lower ad rate, spent less money to air more ads.
The Obama campaign also gambled that it was better to buy ads early in the contest rather than wait until after the conventions — the more traditional route which Romney followed. The president's campaign dominated the airwaves from April through mid-July, when Romney and Republican groups matched and started to exceed the Democratic side.