When cable giant and NBC owner Comcast announced that they were going to buy Time Warner Cable, Comcast figured they would have no problem greasing enough politicians to get the deal approved.

Many others figured the same thing, but now, it looks like what was once a done deal my no longer be the case.

Now, it is unclear whether the U.S. Department of Justice and the Federal Communications Commission will give Comcast their blessing.

"They've had a lot of trouble, more than they thought they would — and rightly so," said Gene Kimmelman, a former top lawyer in the Justice Department's antitrust division who now leads advocacy group Public Knowledge, which opposes the Comcast-TWC merger.

The LA Times writes, here's the rub for Kimmelman and others: The new Comcast would be the nation's dominant supplier of high-speed Internet service. The company would boast 30 million customers in major cities such as Los Angeles, New York, Chicago, Philadelphia, Denver, Dallas, San Francisco and Seattle.

Streaming service Netflix, satellite giant Dish Network, lawmakers and others have voiced concerns that Comcast could use this grip to stifle development of the Internet video business. In a sense, Comcast would have an incentive to beat back online challengers to its core business of bundling cable TV channels.

Meanwhile, a parade of major TV network executives have privately met with federal investigators, outlining their worries about a bulked-up Comcast, according to people involved in the meetings who were unauthorized to speak publicly. They fear Comcast would use its size and influence to undercut how much programmers such as CBS, Viacom and Discovery are paid for their channels.

Comcast, for its part, maintains the regulatory review of its acquisition is proceeding on schedule.

In other words, Comcast still has plenty of grease left and is willing to use it.