Billionaire Rupert Murdoch speculated that the crowd at the Republican presidential primary debate Saturday would be stacked against anti-establishment candidates.

In a tweet Saturday afternoon, Murdoch said it's an old party trick.

"Tonight's audience in S.C. probably rigged by party establishment," Murdoch wrote. "Repeating old tricks from previous elections."

The latest edition of the GOP primary debates takes place at 9 p.m. Saturday in Greenville, S.C., and will last two hours. The debate will be broadcast on CBS.