Donald Trump continued his attacks on former Florida Gov. Jeb Bush over eminent domain and his brother's presidency as former President George W. Bush begins campaigning for his brother in South Carolina. 

Trump on Monday unleashed a series of tweets calling Jeb Bush a "liar" and "just another clueless politician."

On his brother, Trump tweeted: "Now that George Bush is campaigning for Jeb(!). is he fair game for questions about World Trade Center, Iraq War and eco collapse? Careful!"

TV pundits and GOP insiders opined that Trump's attack on the former president in South Carolina was "galactic-level stupid" and the comments "could have jeopardized his lead."

He also accused Bush of using eminent domain and taking "advantage of a disabled vet in the process."

Bush has argued that Trump used eminent domain to build a "limousine parking lot for his casino in Atlantic City."

While Trump, during the debate, dismissed Bush, he referred to eminent domain as "an absolute necessity for a country."

"Without eminent domain, you don't have roads, highways, schools or anything," he said.