Washington (CNN) - In another blow to federal election laws, the Supreme Court on Wednesday eliminated limits on the total amount people can donate to various political campaigns in a single election season. However, the court left intact the current $5,200 limit on how much an individual can give to any single candidate.
At issue is whether those regulations in the Federal Election Campaign Act violate the First Amendment rights of contributors.
The divided 5-4 ruling could have an immediate impact on November's congressional midterm elections, and add another layer of high-stakes spending in the crowded political arena.
"We conclude that the aggregate limits on contributions do not further the only governmental interest this court accepted as legitimate" said Chief Justice John Roberts, referring to a 1976 precedential ruling.
"They instead intrude without justification on a citizen's ability to express the most fundamental First Amendment activities."
Roberts was supported by his four more conservative colleagues.
In dissent, Justice Stephen Breyer said the majority opinion will have the effect of creating "huge loopholes in the law; and that undermines, perhaps devastates, what remains of campaign finance reform."
The ruling leaves in place current donor limits to individual candidates, and donor disclosure requirements by candidates, political parties, and political action committees.
The successful appeal from Shaun McCutcheon, 46-year-old owner of an Alabama electrical engineering company, is supported in court by the Republican National Committee.
They object to a 1970s Watergate-era law restricting someone from giving no more than $48,600 to federal candidates, and $74,600 to political action committees during a two-year election cycle, for a maximum of $123,200.
McCutcheon says he has a constitutional right to donate more than that amount to as many office seekers as he wants, so long as no one candidate gets more than the $5,200 per election limit ($2,600 for a primary election and another $2,600 for a general election).
But supporters of existing regulations say the law prevents corruption or the appearance of corruption. Without the limits, they say, one well-heeled donor could in theory contribute a maximum $3.6 million to the national and state parties, and the 450 or so Senate and House candidates expected to run in 2014.
Opponents of some of the current regulations applauded the court's reasoning.
"What I think this means is that freedom of speech is being upheld," said House Speaker John Boehner (R-Ohio). "You all have the freedom to write what you want to write donors ought to have the freedom to give what they want to give."
“The Supreme Court has once again reminded Congress that Americans have a Constitutional First Amendment right to speak and associate with political candidates and parties of their choice," said Sen.Minority Leader Mitch McConnell.
"Let me be clear for all those who would criticize the decision: It does not permit one more dime to be given to an individual candidate or a party - it just respects the Constitutional rights of individuals to decide how many to support," added the five-term Republican senator from Kentucky, who faces a difficult re-election this year.
But supporters of the limits expressed disappointment.
"The Supreme Court majority continued on its march to destroy the nation's campaign finance laws, which were enacted to prevent corruption and protect the integrity of our democracy," said Democracy 21 president Fred Wertheimer, a longtime advocate for election money reforms. "The court re-created the system of legalized bribery today that existed during the Watergate days."
And Republican Sen. John McCain of Arizona, who last decade co-authored a sweeping law that put in place strict campaign finance limits, said “I am concerned that today’s ruling may represent the latest step in an effort by a majority of the Court to dismantle entirely the longstanding structure of campaign finance law erected to limit the undue influence of special interests on American politics."
The individual aggregate limits were passed by Congress in the wake of the Watergate scandal, and upheld by the high court in 1976.
The current competing arguments are stark: Supporters of campaign finance reform say current federal regulations are designed to prevent corruption in politics. Opponents say they criminalize free speech and association.
The current case deals with direct political contributions. A separate 2010 high court case dealt with campaign spending by outside groups seeking to influence federal elections. There, the conservative majority - citing free speech concerns - eased longstanding restrictions on "independent spending" by corporations, labor unions, and certain non-profit advocacy groups in political campaigns.
The Citizens United ruling helped open the floodgates to massive corporate spending in the 2012 elections. It also led to further litigation seeking to loosen current restrictions on both the spending and donations.
After the high court's oral arguments in October, President Obama had weighed in, saying he supports the current law.
"The latest case would go further than Citizens United," a three-year-old ruling expanding corporate spending, he said, "essentially saying: anything goes. There are no rules in terms of how to finance campaigns.
The case is McCutcheon v. FEC (12-536).
CNN Senior Congressional Producer Deirdre Walsh contributed to this report