Introduction

Carpetbagging super PACs and nonprofit groups are dominating this year’s special congressional elections in a potential foreshadowing of the 2014 midterms, where even the sleepiest locales aren’t immune from out-of-state, cash-flush special interests.

Take Massachusetts’ U.S. Senate election, which last month propelled veteran Rep. Ed Markey, D-Mass., to Congress’ upper chamber — and attracted millions of dollars in outside spending from political groups based in California, New York and Florida.

Organizations in Illinois, meanwhile, spent precisely zero dollars to advocate for or against several candidates who vied early this year to replace ex-Rep. Jesse Jackson Jr., D-Ill., while outfits from everywhere but collectively burned through more than $2 million.

South Carolina? The biggest players backing or bashing eventual House seat winner Republican Mark Sanford, or his Democratic opponent, Elizabeth Colbert Busch, weren’t from Columbia or Charleston, but Washington, D.C.

So far this year, just 4 percent of the $12.4 million spent by political groups or party entities on congressional races came from groups based within the state where they’re doing their spending, a Center for Public Integrity analysis of federal independent expenditure data indicates.

Spending by outside groups has become a pivotal element in elections thanks to the Supreme Court’s 2010 ruling in Citizens United v. Federal Election Commission, which allowed super PACs, unions and certain nonprofits to raise and spend unlimited amounts of money to advocate for or against political candidates.

Washington, D.C., is far and away the biggest source of funding. In all, groups with headquarters in the nation’s capital account this year for about two-thirds of independent expenditures on congressional races. That figure jumps to nearly 72 percent when factoring in organizations from New York City and the D.C. suburbs.

Even homegrown groups usually outsource their work: only three-tenths of a percent of independent expenditures come from in-state groups that also used in-state vendors to produce or manage their advertisements and communications, the Center’s analysis shows.

To illustrate the point, in most cases, state lines are irrelevant when it comes to those who pay for independent ads, those who produce them and even where they air. And it’s not as if states that hosted special elections aren’t home to political consultants.

For example, Independent Women’s Voice, a Washington, D.C.-based nonprofit, paid Illinois firm Victory Media Group to generate $130,000 worth of television advertisements and telemarketing calls primarily slamming Colbert Busch in South Carolina.

Freestone Communications of Missouri — a state that hosted a special election in June — got $64,250 worth of business from the League of Conservation Voters in Washington, D.C., to make phone calls on behalf of Markey in Massachusetts.

And Progressive U.S.A. Voters of Denver paid Grassroots Voter Outreach of Boston more than $21,000 for canvassing services in Illinois’ District 2 Democratic congressional primary.

Most of it targeted Democrat Debbie Halvorson, who lost badly to fellow Democrat and former state Rep. Robin Kelly, the general election’s eventual winner.

Super PACs and nonprofits played a prominent, and sometimes dominant role in many 2012 congressional races, often injecting hundreds of thousands if not millions of dollars of advertising into the elections and sometimes spending more than the candidates themselves.

This flood of outside cash doesn’t sit well with Tim Buckley of the Massachusetts Republican Party, which is one of just three non-candidate committees active in special elections this year that are both based in the state in which they were active and hired in-state help for their advocacy.

Local consultants know their turf better than outsiders and better parse the political intricacies of a state such as Massachusetts, which while strongly Democratic has still elected plenty of Republicans, Buckley argued.

The party paid Campaign Homebank LLC of Boston more than $31,000 for telemarketing services promoting GOP Senate nominee Gabriel Gomez, who lost last month to Markey. It also hired a separate, Virginia-based firm for similar work, paying it about $143,000.

But some outside groups defend their activity as necessary, even healthy, given that congressional candidates hold sway on issues of national interest that reach far behind district boundaries or state lines.

The New York City-based 501(c)(4) nonprofit 350.org Action Fund, which advocates for fighting climate change, made nearly $50,000 worth of independent expenditures in Massachusetts’ special Senate election Democratic primary, supporting Markey over Rep. Stephen Lynch, D-Mass.

Since the Democratic nominees disagreed about the hot button issue of the Keystone XL Pipeline project, the group threw its support behind Markey for rejecting the pipeline, 350.org Action Fund Media Campaigner Daniel Kessler explained.

“We thought it would be important to show that there would be electoral consequences for those that do not oppose the pipeline,” Kessler said.

Looking toward the 2014 midterm elections, early indicators suggest organizations with few geographic ties to key political battlegrounds plan to participate as much or more than ever.

Liberal 501(c)(4) nonprofit Patriot Majority USA and super PAC Senate Majority PAC — both from Washington, D.C. — have together already made more than $277,000 worth of independent expenditures against Senate Minority Leader Mitch McConnell, R-Ky., who faces a potentially tough re-election fight.

Washington, D.C.-based super PAC Club for Growth Action’s independent expenditures have already exceeded $182,000 in opposing U.S. Sen. Mark Pryor, D-Ark.

In opposing Pryor, Club for Growth Action has used vendors for mail production costs and television ads from a range of states including Washington, D.C., Maryland, Virginia and West Virginia.

It’s a practice Keller called “pretty common,” and that Club for Growth Action chose those vendors because of past experiences working together and locations.

“Do you fly to Alabama to get a mortgage?” he asked. “Do you drive to Minnesota to use to the ATM?”

Erin Quinn contributed to this report.