For more than a decade, America’s campaign watchdog agency was a portrait of dysfunction. Divided equally between three Republicans and three Democrats, the Federal Election Commission deadlocked so often it became a political punchline as investigations languished, enforcement slowed and updated guidelines for the internet era stalled.

Now, the commission has suddenly come unstuck.

In a series of recent decisions that are remaking the landscape of money in American politics, an ascendant new bloc of three Republicans and one Democrat is voting together to roll back limits on how politicians, political parties and super PACs raise and spend money.

Reform groups are aghast at what they see as the swift unraveling of longstanding restraints. Conservatives who for years have dreamed of loosening restrictions are delighted, even though many of the rulings were sought by one of the Democratic Party’s most prominent attorneys, Marc Elias, who was seeking political advantage and clarity for his clients.

Those on both sides of the ideological divide agree on one thing: The changes amount to some of the most significant regulatory revisions since the campaign finance law, the McCain-Feingold Act, was put in place two decades ago.

“These decisions are a monumental shift in the law at the commission,” said Sean Cooksey, the Republican chairman of the Federal Election Commission. “The deregulators are winning.”