Presumptive Democratic presidential nominee Hillary Clinton Hillary Diane Rodham ClintonJeff Flake: Republicans 'should hold the same position' on SCOTUS vacancy as 2016 Momentum growing among Republicans for Supreme Court vote before Election Day Warning signs flash for Lindsey Graham in South Carolina MORE's campaign manager on Sunday slammed Donald Trump Donald John TrumpUS reimposes UN sanctions on Iran amid increasing tensions Jeff Flake: Republicans 'should hold the same position' on SCOTUS vacancy as 2016 Trump supporters chant 'Fill that seat' at North Carolina rally MORE, saying the presumptive Republican presidential nominee makes decisions based on what's best for his bank account instead of what is in the best interest of the country.

"In every juncture, he has always done what's best for his own bottom line," Robby Mook said on "Fox News Sunday."

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"And his ideas are a fundamental threat to our economy."

Mook said independent economists say Trump's policies would plunge the country into an "economic ice age."

"I don't think Donald Trump is on the side of any family in the United States, certainly not on their economic side," he said.

"And if we look at how he’s conducted his business, the way that he hasn’t paid small business contractors, the way he's cheated hourly wage workers."

Mook said Trump made a lot of money but has "hurt a lot of people in his wake."

"I think families need to be very skeptical," he said.

"He's certainly on the side of his bottom line and his bank account."

Mook also slammed Trump for his Brexit response, which Mook said shows how Trump would handle issues as president. In response to Britain's vote to leave the European Union, Trump talked about his golf course and said he was "glad the British pound was plummeting because it would help his bottom line," Mook said.

"There's a real contrast here. Hillary Clinton looks at this through the lens of how it's going to affect middle-class families," he said.

"Donald Trump through the lens of how it will help his bottom line and underscores how he is fundamentally unfit to be our next president."