The Senate on Tuesday confirmed President Trump's nominee for deputy Treasury secretary after a key Democrat lifted a hold on the nomination.

The nominee, Justin Muzinich, was confirmed by a largely party-line vote of 55-44.

Muzinich will be the first person to serve as the Senate-confirmed deputy Treasury secretary in the Trump administration. The position is the No. 2 job in the department.

Muzinich has worked at Treasury since early 2017, serving as a counselor to Treasury Secretary Steven Mnuchin. He played a key role in the tax-cut law Trump signed last year.

Republicans have praised Muzinich for his work on the tax law.

Senate Majority Leader Mitch McConnell (R-Ky.) on Monday called Muzinich "well-qualified" and said it's important for Treasury to have a deputy secretary as it implements the new tax law and develops foreign sanctions.

After the Senate Finance Committee advanced Muzinich's nomination over the summer, the committee's ranking member, Sen. Ron Wyden (D-Ore.), placed a hold on it. He had put holds on several Treasury nominees because he felt that Treasury had been "stonewalling" Democrats' requests for information.

Late last month, Wyden announced he was lifting his hold on Muzinich and another Treasury nominee. He said that working with Finance Committee Chairman Orrin Hatch (R-Utah), he reached an agreement under which Treasury has cooperated on several of his information requests.

While Wyden lifted the hold, he and other Democrats, who all opposed the 2017 tax law, largely voted against Muzinich's nomination.

Wyden on Monday criticized Muzinich for saying during his confirmation hearing that the tax cuts will pay for themselves - a claim that has been made by many Republican lawmakers but that many economic analysts across the ideological spectrum say is inaccurate.

"In claiming ... that the Trump tax handouts will pay for themselves, he's failed on that issue by $1.5 trillion. I am not going to support a nominee for this position who is going to bring unicorn and rainbow fantasies to tax policy," Wyden said.

Wyden also criticized Muzinich for defending Treasury Department guidance that reduces the amount of information that certain tax-exempt groups have to disclose on annual forms to the IRS. Muzinich said that the goal of the guidance was to make tax administration more efficient, but Wyden and other Democrats are worried that the guidance will make it easier for foreign governments to influence U.S. politics.

Wyden and Sen. Jon Tester (D-Mont.) have offered a measure to overrule the Treasury guidance that is expected to get a vote this week.