Daily fantasy sports have come under scrutiny after a DraftKings employee posted nonpublic information about a contest, fueling concerns that he may have used that information when he won $350,000 at rival site FanDuel in a previous bet.
In fact, the Nevada Gaming Commission put a block on DraftKings and FanDuel, saying they cannot operate in the state until they obtain their gambling license.
"When you have insider information ... people use that information; use big data to take advantage of it [and] there has to be some regulation," Bush said.
Still, New Jersey Gov. Chris Christie was baffled by the fact that the topic was discussed at the debate. "Are we really talking about ... daily fantasy football?" he said. "We have $19 trillion in debt, we have people out of work, we have ISIS and al-Qaeda attacking us, and we're talking about fantasy football?"
—CNBC's Eric Chemi and Nicholas Wells contributed to this report.
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