Disney and Comcast are separately bidding for many of Twenty-First Century Fox's assets, according to various people familiar with the talks, but none of it matters if the ultimate deal won't pass federal scrutiny. Look at the issue AT&T is having as it tries to close its $85.4 billion deal for Time Warner.

However, because of Disney's classification as a media company and growing competition from technology companies entering the media space, it may have the better shot getting a deal that doesn't violate anti-trust laws.

"I believe the DOJ would be especially interested in this deal because Comcast is America's largest provider of cable and internet services, and Comcast already owns Universal Studios and other content providers, such as NBC," said Randall D. Smith, professor at the Missouri School of Journalism at the University of Missouri. "My thinking is Disney makes the most sense, but Disney will most likely have to shed some assets to satisfy the regulators, their competitors and the politicians. The question will be: 'What might they be willing to give up?'"

Sources previously told CNBC that Disney was close to a deal to purchase parts of Twenty-First Century Fox, including network Nat Geo, Asian pay TV operator Star TV, movie studios, stakes in Sky and Hulu, and regional sports networks. It would not include news and business news divisions, its broadcast network and Fox Sports. The deal, could be worth more than $60 billion including the assumption of debt, could be announced early next week.

Comcast has also thrown its hat in the ring. The company is most interested in British pay-TV operator Sky because of its technology capabilities. Comcast wants to diversify its business outside the United States, which this deal would allow.

Fox selling to Disney could also give shareholders a better payout. Current Fox shareholders would get shares of the remaining Fox company plus shares of Disney, according to sources. Disney is currently trading at $104 a share, while Comcast is just shy of $38. Assuming Comcast terms are similar, shareholders have more to gain if Fox goes with Disney.

But Comcast's biggest problem is it owns too many huge assets already, and adding Fox may make it too big a force, said Seth Kaplowitz, a lecturer at San Diego State University and international law attorney.

Given there are so few telecommunications companies Comcast's size, adding Fox would make it even larger and potentially a monopoly. On the other hand, there are many more media company competitors. Adding a few pieces of Fox to Disney won't tip the scales as much.

"Disney can be a bit more flexible," Kaplowitz said. "Comcast is walking through a bigger hornet's nest."

The deal also would give Disney more content for its upcoming streaming platform. The company is pulling its content away from Netflix by 2018, signifying the increased competition from subscription services that don't require cable or satellite. It also gives Disney an argument that adding Fox will allow it to remain competitive against technology companies who are adding content services.

"The new competition has expanded greatly on the distribution front," said Gene Del Vecchio, professor at USC Marshall School of Business and a movie business consultant. "Netflix, Apple, Google decided they want to use their distribution chain to distribute content. The way you define the marketplace is much much larger."

However given the Department of Justice lawsuit against the AT&T-Time Warner merger, there is a high chance that any Fox deal will be closely looked at. If the government blocks AT&T's deal, it may crack down on any Fox deal, whether with Disney or Comcast.

"If Al Franken didn't resign, he was one of the experts on the Senate on net neutrality and these type of acquisitions," SDSU's Kaplowitz said. "Unfortunately there's not anyone who had the depth of knowledge he has. This, like everything, is going to turn out to be political. The barometer is going to be what happens with Time Warner and AT&T."

Disclosure: Comcast is the owner of NBCUniversal, parent company of CNBC and CNBC.com. Comcast is a co-owner of Hulu.