NEW YORK — That didn’t take long.

A day after a federal judge cleared the way for AT&T’s takeover of Time Warner, Comcast made a bold all-cash $65 billion offer for Fox assets, setting up a clash with Disney and becoming the first big media company to attempt what is expected to be a spate of new megamergers.

The battle for Twenty-First Century Fox reflects a new imperative among entertainment and telecommunications firms, which are amassing ever more programming to better compete with technology companies such as Amazon and Netflix for viewers’ attention — and dollars. Comcast’s offer shows that it’s willing to bet big to try to get its hands on the right content creators and distributors.

In a call with investors, CEO Brian Roberts said the marriage of Fox and Comcast would create the “entertainment company of the future.”

Comcast says its bid is 19 percent higher than Disney’s $52.5 billion stock offer made in December, although the final value will depend on Disney’s share price at the closing. Fox said it would review Comcast’s offer. Shareholders were set to vote on Disney’s offer on July 10, but Fox is considering whether to postpone or cancel that meeting.

On Tuesday, Judge Richard Leon rejected the government’s argument that the AT&T deal would hurt competition in cable and satellite TV and jack up costs to consumers for streaming TV and movies. His ruling signaled that Comcast can most likely win regulatory approval as well.

“This is a golden offer that will put considerable pressure on (Disney CEO Bob) Iger and Disney to step up their game on another bid,” GBH Insights analyst Dan Ives said. The higher-than-expected bid, he said, “speaks to Comcast really wanting these key assets.”

If the Comcast bid succeeds, it would give a major cable distributor control over even more channels on its lineup and those of its rivals. That could lead to higher cable bills or make it more difficult for online alternatives to emerge, although so far there’s no evidence of either happening following other mergers.