WASHINGTON — The 2014 midterm elections mark a new level of collaboration between candidates and independent groups, eroding the barrier that is supposed to separate those running for office from their big-money allies.

The vast sums of cash raised by independent groups has reordered the political landscape, compelling campaigns to find new ways to communicate their wants and needs without officially coordinating with outside players. Such direct coordination is prohibited under 40-year-old campaign finance rules.

This is not how the system used to work. Just a decade ago, candidates shied away from being too closely associated with “soft money,” for reasons of appearance and for fear of running afoul of election laws.

But the rapid spread of super PACs and politically active nonprofit groups that followed the Supreme Court’s Citizens United decision has dramatically altered the climate. Political operatives are also taking advantage of the hands-off approach of a divided Federal Election Commission, which has not reexamined coordination rules in the wake of the 2010 ruling.

“There is a lot of boldness,” said Larry Norton, a campaign finance lawyer at the law firm Venable who served for six years as the FEC’s general counsel. “It’s partly a function of very sketchy rules and regulations and little enforcement. People aren’t sure where the lines are.”

In that void, candidates and independent groups have sought to bring their operations in alignment as much as possible this year.

To help allies fashion their plans, Democratic and Republican congressional committees posted detailed opposition research books and talking points about individual candidates on their websites. And it is now standard practice for candidates to share suggested television ad scripts and video footage online – materials that are then scooped up by outside groups and turned into television spots.

This year also saw the rise of single-candidate super PACs, flush with cash from a contender’s family and friends. More than 90 such groups sprung up to back candidates in 2014, up from 21 four years ago, according to FEC data compiled by the Center for Responsive Politics.

The closeness between candidates and their wealthy backers threatens a principle embraced by Congress after the Watergate scandal – that rich donors should not be able to give unlimited sums to an elected official.

“I think the increasing degree of interaction between candidates and outside groups is rendering the candidate contribution limits meaningless,” said Paul S. Ryan, senior counsel for the Campaign Legal Center, which has filed complaints with the FEC about the widespread use of shared video footage this year.

Michael Toner, a former FEC commissioner who helped rewrite the agency’s coordination regulations after Congress overhauled campaign finance rules in 2002, said stopping candidates and independent groups from openly disseminating their plans would be impossible “unless you want to make it illegal to use information in the public sphere.”

“And I don’t know how that would be manageable or constitutional,” said Toner, a Republican campaign finance lawyer at Wiley Rein.

The interplay between both sides is only likely to increase in the 2016 elections, when personalized super PACs and other outside players are expected to be ubiquitous.