A top White House economic adviser predicted Thursday that President Obama's tax-cut deal with Republicans would pass Congress before Christmas.

Lawrence Summers — the outgoing chairman of the National Economic Council — indicated that momentum on Capitol Hill is building in favor of the plan.

"I think the right thing is going to happen here," he said during an interview with CNBC. "It's an important compromise, and I expect we'll see it in law before Christmas."

Summers's comments show the White House senses it could be gaining the upper hand in the battle over the expiring Bush-era tax cuts on Capitol Hill after the package initially appeared in danger of failing. 

The administration has been aggressive in its push for the deal, which it wants completed before the lame-duck session ends this month. President Obama has made multiple public speaking appearances and the White House press office has blasted out 30 endorsements of the deal by lawmakers and other public officials in both parties.

In addition, a number of Senate Democrats who criticized the deal on Wednesday left the door open to eventually supporting the compromise, and only two have said outright that they oppose the accord, which would extend all the cuts for two years in exchange for a 13-month extension of unemployment benefits.

But the package appears to be in greater trouble in the House, where Democrats have vented frustration about the politics and substance of the deal, and at least 54 members have said they oppose it.

Vice President Joe BidenJoe BidenTrump shakes up WH communications team The Hill's Campaign Report: Wisconsin votes despite coronavirus pandemic The Intercept's Ryan Grim says Cuomo is winning over critics MORE made a second trip to the Hill this week in an attempt to ease tensions with Democrats in the lower chamber. But he also took a hard line with the caucus, telling its members the deal will not be changed.

Despite that opposition, Rep. Barney Frank (D-Mass.) predicted Wednesday the deal would eventually pass.

Summers — who has warned that failure to pass the proposal could lead to a "double-dip" recession — said the plan is the right thing to do in the short-term to get the economy back on its feet.

"You know, if you added up the payroll tax holiday, the extension of unemployment insurance, the expensing of business investment, the continuation of the Bush middle-class tax cuts, this is a program that really is going to give the economy a substantial shot in the arm at a time when that's what we need," he said.