Marathon markup sessions in December have revealed deep fissures among Republicans on a bill championed by House Judiciary Chairman Lamar Smith (R-Texas) that is designed to combat Internet piracy.

The issue cuts across party lines as well.

A top Republican warned that the legislation threatens the very future of the Internet. Other GOP Members said it could cripple cybersecurity efforts. Democratic Rep. Zoe Lofgren (Calif.) was so enraged that she used a procedural move to force a committee aide to read the full text of the bill.

Smith, however, ceded nothing to critics.

“The criticism of this bill is completely hypothetical; none of it is based in reality. Not one of the critics was able to point to any language in the bill that would in any way harm the Internet. Their accusations are simply not supported by any facts,” Smith said in a statement.

Members and aides said the move was typical for Smith, who is famously steadfast, even “stubborn,” as some Republicans on the Judiciary Committee privately said, once he has determined a course on legislation.

Asked for a response to the bill’s vehement critics on Internet sites such as Reddit, Smith told Roll Call, “It’s a vocal minority. Because they’re strident doesn’t mean they’re either legitimate or large in number. One, they need to read the language. Show me the language. There’s nothing they can point to that does what they say it does do. I think their fears are unfounded.”

Smith’s tenacity would seem to leave opponents with few options.

As Rep. Bob Goodlatte (R-Va.) noted when asked about GOP critics of the bill, “Well, but, you’ve seen the amendment votes so far. The committee’s pretty strongly behind the chairman.”

Smith had the votes he needed to defeat amendments that would have substantially changed the law.

But heading into the new year, the legislation will face a major crossroads: what GOP leaders think

Majority Leader Eric Cantor (R-Va.) and Majority Whip Kevin McCarthy (R-Calif.) have taken an interest in Internet and technology issues as part of their Young Guns brand and made inroads with Silicon Valley executives, including taking a September trip to Facebook’s Palo Alto, Calif., headquarters.

Cantor has quietly appealed for support in Hollywood in recent years, and McCarthy has closely monitored the entertainment industry from his days in the California Assembly.

But the legislation pits the film and entertainment sector against Internet giants such as Google and Facebook.

Members and aides on both sides of the issue say GOP leaders have thus far stayed out of the debate.

The “most important thing [is], they haven’t told me not to go forward. I’m expecting support,” Smith told Roll Call.

But that’s not to say his party’s leaders in the House won’t take a keener interest once Smith reports the bill out, a crossroads that could determine whether the bill lives on or withers on the vine.

In the meantime, Smith might need to repair a few relationships after tempers flared during the markup sessions.

Members complained about the amount of time the committee spent consulting experts before moving to mark up the legislation.

“It’s time to pull the nerds in,” Rep. Jason Chaffetz (R-Utah) said.

“There’s an opportunity to negotiate, even big bills like this, before the markup commences. And your chances of being successful are greater in those negotiations than they are in the open debate,” Rep. Steve King (R-Iowa) said.

Rep. Dan Lungren (R-Calif.) said the intensity of the criticism was in part caused by the short amount of time the committee had to deal with the issue.

“We’ve had controversy over bills before that are dealing with a comprehensive topic, but we’ve always had more time to deal with them, so that the kinds of large differences that you see laid out here have been taken care of in the past,” Lungren said.

Rep. Darrell Issa (Calif.) was the boldest Republican critic of the bill. For instance, Issa changed the profile picture of his Facebook page to a black box with “censored” in white letters to protest the bill.

Smith said only, “I’m very pleased with the way the markup is going” in response to his provocative GOP opponents.

Chaffetz said it’s “fair enough” to say Smith is uniquely tenacious in weathering criticism and holding fast to a decision but that his winsome personality makes up for any bruised feelings caused by that trait.

“He does it in a manner that’s not offensive to anybody. He’s the nicest guy in the world. He believes in this, and he wants to push the bill, and he’s the chairman. So I don’t fault him for that,” Chaffetz said.