Donald Trump has blamed faulty interpretations and media bias for an uproar over his comments about the Second Amendment.
He is insisting he never advocated violence against Hillary Clinton, even as undeterred Democrats pile on.
The latest controversy to strike Mr Trump's campaign arose, as they often do, out of an offhand quip at a boisterous campaign rally.
Claiming falsely that Ms Clinton wants to revoke the right to gun ownership guaranteed in the Constitution's Second Amendment, Mr Trump said there would be "nothing you can do", if she is elected, to stop her from stacking the Supreme Court with anti-gun justices.
Then he added ambiguously: "Although the Second Amendment people, maybe there is - I don't know. But I'll tell you what: that will be a horrible day."
Like so many times before, Mr Trump's supporters and opponents construed his comments in entirely different ways.
"Give me a break," Mr Trump said hours later, insisting he was referring to the power that voters hold. He told Fox News that "there can be no other interpretation".
But Democrats saw - and seized - an opportunity to reinforce the perception that Mr Trump cannot moderate the things that come out of his mouth, much less the decisions he would make as president.
"I really, frankly couldn't believe he said it," said Tim Kaine, the Democratic vice presidential nominee.
"Nobody who is seeking a leadership position, especially the presidency, the leadership of the country, should do anything to countenance violence, and that's what he was saying."
By Tuesday evening, Ms Clinton's campaign was fundraising off the firestorm, asking supporters by email to chip in one dollar to "show that we don't tolerate this kind of politics in America".
Mr Trump's team, too, was using the controversy to reinforce a theme it has been pitching to voters: that an underdog Trump is being unfairly treated by the media.
"They will buy any line, any distortion, and spin that the Clintons put out," said former New York Mayor Rudy Giuliani, an ardent Trump supporter.
But House Speaker Paul Ryan, who was celebrating a primary victory in Wisconsin on Tuesday night, said: "It sounds like just a joke gone bad. I hope they clear this up very quickly. You never joke about something like that."
The controversy immediately overwhelmed Mr Trump's intended campaign-trail focus: the economic plan he unveiled just a day earlier and was promoting during rallies in the most competitive election states.
It also underscored the concern, voiced by many worried Republicans, that he cannot stay disciplined and avoid inflammatory remarks that imperil not only his White House prospects but the re-election chances of many Republican lawmakers.
It was not immediately clear whether Mr Trump's latest stumble would continue to dog him or whether, like many in the past, it would quickly fade away.