Study: Anti-ObamaCare ads might have increased sign-ups

Millions of dollars in conservative ads against ObamaCare might have backfired and actually boosted enrollment in key states, according to a new study

A fellow with the Brookings Institution found a "positive association" between ad spending against ObamaCare and enrollment in health plans under the law. 

The trend appeared strongest in states with competitive Senate races this year, where conservative groups are spending widely on ads against the Affordable Care Act. 

In states where Senate Democrats are up for reelection, ad spending against the law correlated with higher enrollment, the study found. 

The opposite was true in states where Senate Republicans are defending seats. 

"While the negative ads reduce the enrollment in red states, they have an opposite effect in blue states," wrote Brookings fellow Niam Yaraghi, the study's author. 

The analysis sheds light on one of the chief political dynamics of the 2014 elections. 

Republicans and their allies are hoping that public opposition to the healthcare law will benefit their candidates at the polls. As a result, groups like Americans for Prosperity have spent millions of dollars on ads that criticize ObamaCare and its faulty rollout. 

Those ads have become less frequent as the political debate shifts away from healthcare this year. Still, if they did boost enrollment in states where Senate Democrats are on defense, it's possible those incumbents will see additional support from people with new ObamaCare plans. 

Republicans argue that ObamaCare's persistent lack of popularity will remain the deciding factor for many Democrats, regardless of how many people enrolled in their states. 

The Brookings study was published on Wednesday.