Ad spending on immigration is only a fraction of what was spent on health care reform. Over the first 10 months of 2009, $166 million was spent on TV ads on health reform alone, according to CNNMoney. The amount of ad money on TV and radio spent on immigration over the past three months only totaled $7.8 million.
"That's been the one part that is lagging. There hasn't really been money flowing into this fight," said Culling. "The frustration is that there is so much money that's in support of immigration, but it won't get off the sidelines."
There will be increased efforts, however, to give cover to Republican lawmakers as the debate moves to the House.
Republicans for Immigration Reform is a super PAC founded by former Bush Commerce Secretary Carlos Gutierrez. But the group has remained relatively quiet during the first half of the year (except for this ad backing Sen. Graham).
The group's executive director, Charlie Spies, said that it plans to ramp up efforts in the House. The group will run more ads in select congressional districts, where members may come under fire from conservatives and Tea Party groups for backing immigration reform.
"We believe there is a value to Republicans on the fence knowing that there are going to be people who have their backs when they come out in favor of reform," Spies said. "The shrill minority of people who are attacking them aren't representative of Republicans as a whole, or their constituents."
But don't expect health care levels of ad-spending. Spies, who formerly ran a super PAC that backed GOP presidential candidate Mitt Romney, does not anticipate a flood of political advertising on immigration … at least not this year.
"[O]ur purpose was always to provide air cover to Republicans that get attacked for supporting reform when it matters most," he said. "And that's going to be next year during the election cycle, when people are paying attention."
3. Go on the attack
Of course, there's another way to sway House Republicans: Spend money to attack their stance on immigration. But so far, advocacy and lobbying groups have avoided the negative approach.
"We have not had to do what I think we would do on other issues, which is to say we'll withhold support or support a challenger," said Jeremy Robbins, director of the pro-immigration Partnership for a New American Economy and a policy advisor to New York City Mayor Michael Bloomberg.
Robbins said that doesn't mean attack ads are entirely off the table. He's willing to embrace whatever strategy makes the most sense. But, for now, his organization is taking a friendlier tack. "We would much rather work with a target than against a target," he said.
There's another reason you might not see ads shaming conservatives who oppose immigration reform: They might not work that well.
While immigration is a core issue for Latinos, it's less important for other groups. So it wouldn't make sense to air ads on a topic that doesn't stir enough voters to action. Plus, attacks could turn off fence-sitting GOP congressmen, according to Spies, of Republicans for Immigration Reform.
"We don't anticipate going on offense at this point," he said. "There are enough persuadable Republicans that can weigh in and we can work with those who are open to a comprehensive approach to reform that its not a productive use of resources to attacking Republicans whose minds aren't going to be changed."