On April 2, 2014, the Supreme Court ruled in the case of McCutcheon v. Federal Election Commission striking down limits in federal law on the overall campaign contributions the biggest individual donors may make to candidates, political parties and political action committees.
The justices said in a 5-4 vote that Americans have a right to give the legal maximum to candidates for Congress and president, as well as to parties and PACs, without worrying that they will violate the law when they bump up against a limit on all contributions, set at $123,200 for 2013 and 2014. That includes a separate $48,600 cap on contributions to candidates.
But their decision does not undermine limits on individual contributions to candidates for president or Congress, now $2,600 an election.
You can read more details about McCutcheon v. FEC, 12-536 here.