President Barack Obama on Wednesday suggested amending the U.S. Constitution to undo a Supreme Court decision that allows unlimited spending on elections by corporations, unions and anyone else who can write a big check, looking to highlight the influence of money in politics even as there is little he can do about it this election.

“We are seeing something new in the no-holds barred flow of seven and eight figure checks, most undisclosed, into super PACs; they fundamentally threaten to overwhelm the political process over the long run and drown out the voices of ordinary citizens,” Mr. Obama said during a question-and-answer session he conducted on Reddit.com. Mr. Obama said he wants legislation that prohibits lobbyists from bundling campaign contributions and thinks super PACs should disclose who is funding them.

“Over the longer term, I think we need to seriously consider mobilizing a constitutional amendment process to overturn Citizens United,” Mr. Obama said. He added, “Even if the amendment process falls short, it can shine a spotlight of the super-PAC phenomenon and help apply pressure for change.”