WATCH: Jittery Ted Cruz spooked as Beto O’Rourke schools him on economics and political corruption

Sen. Ted Cruz (R-TX) was visibly flustered during Tuesday night's Texas Senate debate when Rep. Beto O'Rourke linked the conservative senator's vote to increase the budget deficit to accepting money from Political Action Committees (PACs) that represent corporate interests.

"He voted to add $2 trillion dollars," O'Rourke said while answering a question about America's debt, which has mushroomed since Republicans passed a controversial tax cut.

"And those tax cuts disproportionately will flow to corporations who are already sitting on record piles of cash, and the already wealthy -- in a country that is already riddled with income inequality unseen since the last Gilded Age," O'Rourke noted.

"Why?" he asked, rhetorically.

"In the days just before and just after that vote, Sen. Cruz accepted $120,000 from the Political Actions Committees who represent the corporate interests that benefited from this tax cut," O'Rourke charged.

Cruz chortled nervously and began tapping his fingers -- six times -- on his transparent lectern.

"Follow the money," O'Rourke suggested.

"I don't take PAC money, not a dime," he added. "I only represent the people of Texas."

Watch: