President Obama has tapped Brian Deese, his senior adviser on energy and environment issues, to oversee the upcoming Supreme Court nomination, the White House announced Monday.

Deese, who played a key role in forging the Paris climate agreement in December and served as acting director of the Office of Management and Budget before taking on his current post a year ago, faces the daunting task of filling the current vacancy on the court when Senate GOP leaders have declared they have no interest in holding hearings or a vote on any Obama nominee.

While other administrations have typically tapped outside advisers to serve as “sherpas” for their Supreme Court picks, the president has typically handled these questions in-house. Deese, a graduate of Yale Law School, finished his degree while working for the White House during Obama’s first term and helping spearhead the bailout of U.S. auto firms. Rather than practicing law full time after graduation, he has focused on first economic, and then environmental, policy for the administration.

“The president has relied on Brian in a variety of critical situations,” White House press secretary Josh Earnest told reporters at his daily briefing. “Early in the administration, Brian played a key role in the auto task force. Those were tough decisions the president had to make early on.”

Earnest noted that Deese devoted most of last year to helping broker the U.N. climate agreement that aims to curb global carbon emissions in the next decade. He described the pact as “a testament to Brian’s hard work,” adding that while many U.S. officials played a role in the process, Deese “deserves a lot of credit” for securing the deal.

Alongside of Deese, according to a White House official who asked not to be identified in order to discuss internal deliberations, White House counsel Neil Eggleston will oversee legal efforts including the search, review, research, and vetting of candidates. The group will report to White House chief of staff Denis McDonough, the president’s senior advisers and Obama on a regular basis.

More broadly, Earnest said the president is continuing to cast a wide net as he eyes different candidates to fill the vacancy left by the sudden death of Justice Antonin Scalia. “The president did spend a significant period of time reviewing materials and considering potential candidates”over the weekend,” he said, but has yet to finalize a short list of names.

Obama will meet Tuesday at the White House with both Senate Majority Leader Mitch McConnell (R-Ky.) and Senator Minority Leader Harry Reid (D-Nev.), and the top Republican and Democrat on the Senate Judiciary Committee, Charles E. Grassley (R-Iowa) and Patrick J. Leahy (D-Vt.).

“He’s going to spend plenty of time talking to members of Congress,” Earnest said of Obama, adding the president and other administration officials would also spend time “talking to people outside of Congress.”