Updated

The co-chairs of a budget "supercommittee" responsible for coming up with at least $1.2 trillion in deficit cuts announced Tuesday that they have chosen a Republican tax expert as their top staff aide.

Sen. Patty Murray, D-Wash., and Rep. Jeb Hensarling, R-Texas, have selected Mark Prater, a tax lawyer with the Senate Finance Committee, as the supercommittee's staff director. They said in a joint statement that Prater's two decades of experience as a top GOP aide on the panel bring the know-how and experience required to help the supercommittee succeed.

""Mark has a well-earned reputation for being a workhorse who members of both parties have relied on," Murray and Hensarling said. "We look forward to working with him and are confident that his approach and expertise will be valuable as we weigh the difficult but necessary choices ahead."

The supercommittee was established under legislation enacted last month to increase the government's ability to borrow. It is charged with finding at least $1.2 trillion in deficit cuts as a condition for President Barack Obama to be allowed to order further debt limit increases. If the committee, which is evenly split between Democrats and Republicans, deadlocks or if Congress fails to enact its recommendations by Christmas, automatic spending cuts covering both defense and domestic accounts would be triggered starting in 2013.

Prater is highly thought of on Capitol Hill. He assisted lawmakers in the drafting of tax legislation such as the Bush-era cuts in taxes on income, investments, married couples and families with children. And he can play the three-dimensional chess that's needed to help lawmakers do the deals required to forge consensus on complicated legislation. He's also steeped in the minutia of various tax breaks and preferences that many lawmakers say are wasteful and inefficient.

"Mark has built a well-deserved reputation as an honest broker -- not just a `Republican staffer' -- well capable of finding the middle ground and producing results," said Bill Dauster, a top adviser to Senate Majority Leader Harry Reid, D-Nev. "His longstanding relationships with folks on both sides of the aisle will serve him and the Joint Committee well as they do their important work."

The Finance Committee which Prater serves has sweeping jurisdiction over taxes and federal health care programs.

Separately, GOP aides said the Republicans on the panel were holding a strategy session Tuesday in advance of an official first meeting of the committee next month.