Democrats have raised over $13,000 (£10,700) online to repair a Republican Party office in North Carolina that has been damaged by a "firebomb".
The funds were raised in under 40 minutes On Monday morning, according to an update posted to the GoFundMe page.
A bottle filled with flammable liquid was thrown through the window of the Orange County Republican Party headquarters on Sunday, the party said.
"Nazi Republicans get out of town or else," was written on the building.
No-one was hurt, but a security alert was sent to other offices, said state Republican director Dallas Woodhouse.
On Monday the Democratic fundraisers wrote online: "Until an investigation is undertaken, we cannot know who did this or why. No matter the result, this is not how Americans resolve their differences. We talk, we argue, sometimes we march, and most of all we vote. We do not resort to violence by individuals or by mobs."
The fundraisers surpassed their goal, and quickly closed down the posting, preventing further donations to their political rivals.
"Thank you all for showing that Americans are thirsty for civility and decency, and that we love our democracy above all our differences," organizers wrote, directing further donations to other charities in North Carolina.
Democratic presidential candidate Hillary Clinton said in a tweet the attack was "horrific and unacceptable".
But the Republican nominee, Donald Trump, appeared to blame Democratic supporters for the attack.
"Animals representing Hillary Clinton and Dems in North Carolina just firebombed our office in Orange County because we are winning @NCGOP," he said on Twitter.
Mr Woodhouse said the bottle landed near a sofa where volunteers often take naps.
"They are working around the clock. It is a miracle that nobody was killed", he said, calling the fire an act of "political terrorism".
Local police said they were investigating the incident alongside the Bureau of Alcohol, Tobacco, Firearms and Explosives.
Tom Stevens, the Democratic mayor of the town, Hillsborough, condemned the act in a statement.
"This highly disturbing act goes far beyond vandalising property; it wilfully threatens our community's safety via fire, and its hateful message undermines decency, respect and integrity in civic participation," he said.
North Carolina is a key battleground swing state that has been visited by Mrs Clinton and Mr Trump four times each in the last month.
President Barack Obama campaigned for Mrs Clinton last week in the state, which he narrowly won in 2008 and lost by two points in 2012.
Mr Trump and Mrs Clinton are locked in a tight race in the Tar Heel state, with polls showing the Democrat with a less than 3% lead.