The Trump administration's protracted battle to fill its Cabinet scored an important victory with the confirmation of Rep. Mick Mulvaney as director of the Office of Management and Budget.

Mulvaney, R-S.C., — a budget hawk in the House of Representatives — secured confirmation in a narrow 51-49 Senate vote on Feb. 16, when normal GOP stalwart Sen. John McCain, R-Ariz., wavered in supporting the nominee.

The confirmation comes on the heels of a pair of big losses for the Trump administration with the resignation of National Security Adviser Michael Flynn and the withdrawal of Labor Secretary nominee Andrew Pudzer.  

The congressman will be tasked with some of the administration’s headiest objectives, including crafting policy to reduce the size of the federal workforce by attrition and an expected massive reorganization of agency operations.

Mulvaney’s nomination courted controversy for his past stances in the House on thorny issues like sequestration and the 2013 government shutdown.

Sen. Mark Warner, D-Va., voted against the congressman’s nomination, but said in a statement that he planned to work with Mulvaney, despite concerns about his views on the federal budget.

"Though I voted against this nomination, I recognize there are areas of agreement where I believe Rep. Mulvaney and I can work together," Warner said.

"For instance, he has provided assurances of support for oversight of how the federal government uses and reports financial data as required by the DATA Act, and for pushing for more open and data-driven operations across federal agencies."

Despite expected Democratic resistance, the most notable name to vote against Mulvaney was McCain, who said on Feb. 15 that the congressman’s past support of defense cuts was a deciding factor.

While the remainder of the Trump administration’s nominees will be closely watched, the OMB role will be central to both the White House’s regulatory policy and its vision for the future of the federal workforce, with stakeholders eager to see Mulvaney’s approach to the role.

"Effective government requires coordination from the center, and OMB is best positioned to provide that leadership," Partnership for Public Service President and CEO Max Stier said in a statement.

"I am hopeful that Director Mulvaney will embrace the critical role played by OMB to improve the operations and management of our government. We congratulate Mr. Mulvaney on his confirmation and look forward to working with him to boost government performance and better serve the American public."