After dragging its feet for four years, the federal agency that regulates campaign spending is finally moving to conform with a landmark Supreme Court decision that dramatically loosened election spending rules. 

The leaders of the Federal Election Commission announced the agreement on Thursday. It marks the apparent end of a protracted deadlock on the panel over how to comply with the controversial 2010 Citizens United ruling, which lifted restrictions on corporate and union spending in elections. 

The agreement also gets the FEC on the same page with the more recent McCutcheon decision, which overturned aggregate contribution limits for donors. 

"This has been a long time coming for the commission," Chairman Lee Goodman told FoxNews.com. 

Political groups have not exactly been waiting on the FEC to update its rulebook. The Citizens United decision triggered a flood of new election spending and the proliferation of so-called "super PACs." 

But Goodman said that for all this time, lawyers and others who look to the FEC for guidance nevertheless have been relying on "inaccurate and unconstitutional regulations" that have remained on the books despite those rulings, causing confusion. The new agreement would roll back those outdated restrictions. 

"I think today we crossed the Rubicon," he said. "It's also a good day for the Constitution." 

Commission leaders are hoping to formally vote on the updated regulations at an Oct. 9 meeting, and claim to have a majority to do so. 

What took so long is a matter of debate. National Journal reported over the summer that the biggest sticking point on the commission had been over how exactly to overhaul spending limits in the wake of Citizens United. Republicans reportedly wanted to strip the overturned provisions outright, while Democratic members wanted to still include disclosure requirements. 

While the FEC gets up to date, the rulings continue to serve as a political football. 

Though both sides of the aisle have arguably benefited from Citizens United-fueled super PACs, Democrats say it's allowed big spenders to unfairly tilt elections. Senate Democrats this week set out on a doomed election-year bid to pass a constitutional amendment aimed at curbing such spending, but it died in the Senate on Thursday, as expected.