The court did not strike down contribution limits per candidate (now $2,600) and per party committee (now $32,400), but the decision does overturn previous rules that restricted individuals from giving those maximum donations to dozens of candidates and several party committees.
This meant that wealthy donors would have to be more selective about whom they contributed to -- contributing to House Democrats' campaign committee, for instance, but not Senate Democrats'.
In its decision, the court compared the overall contribution limits to restricting the number of candidates a newspaper can endorse.
"Contributing money to a candidate is an exercise of an individual's right to participate in the electoral process through both political expression and political association," the justices wrote. "A restriction on how many candidates and committees an individual may support is hardly a 'modest Restraint' on those rights. The Government may no more restrict how many candidates or causes a donor may support than it may tell a newspaper how many candidates it may endorse."
The decision could also affect overall contribution limits imposed by states on non-federal elections.
Campaign finance watchdogs and lawmakers who favor limiting the influence of money in politics were quick to decry to ruling.
Sen. John McCain (R-Ariz.) called Wednesday's ruling "predictable" given that the Supreme Court had previously struck down elements of the campaign finance reform bill he wrote and sponsored.
"I was deeply disappointed, but it is what it is," McCain said shortly after the ruling was announced. "I predict again, there will be major scandals in campaign finance contributions that will cause reform."
"There will be scandal," he repeated. "There's too much money washing around."
Democrats generally agreed.
“This in itself is a small step, but another step on the road to ruination,” said Sen. Charles E. Schumer (D-N.Y.), who said the ruling “could lead to interpretations of the law that would result in the end of any fairness in the political system as we know it.”
Most Republicans, though, praised the ruling for allowing Americans to have more voice in the political process through political donations.
"Today's Court decision in McCutcheon v. FEC is an important first step toward restoring the voice of candidates and party committees and a vindication for all those who support robust, transparent political discourse," said Reince Priebus, the chairman of the Republican National Committee.
House Speaker John Boehner (R-Ohio), in comments after the decision, derided the campaign finance law McCain helps spearhead, known as "McCain-Feingold," and praised the Supreme Court.
"What I think this means is that freedom of speech is being upheld," Boehner said. "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."
Ed O'Keefe contributed to this report. Updated at 11:11 a.m.
Here's the decision: