Conservative Sen. Jeff Sessions (R-Ala.) is expected to temporarily replace party-switcher Sen. Arlen Specter (Pa.) as the top Republican on the Judiciary Committee.

Under a deal with Sen. Chuck Grassley (R-Iowa), Sessions will take over for Specter for the remainder of this Congress but relinquish the ranking member slot in 2011 to become the top Republican on the Budget Committee. Grassley is more senior on Judiciary but currently serves as the ranking member on the Finance Committee.

The agreement means Grassley would take the top slot on Judiciary at the beginning of the 112th Congress.

Sessions and Grassley were expected to meet Monday afternoon to formalize their arrangement, sources said.

Specter’s defection last week from the Republican Party had threatened to set off an intraparty feud between conservatives — who favor Sessions — and old-line moderates, who had preferred Grassley.

But Grassley, as the ranking member on Finance, is in the middle of the health care reform debate and in a plum position from which to rake in millions in campaign contributions. Facing re-election in 2010, Grassley was reluctant to give up his powerful Finance post. Grassley is prevented by GOP term limits from keeping the Finance ranking membership in 2011.

Grassley originally tried to recruit Sen. Orrin Hatch (R-Utah) to keep the Judiciary ranking member job warm for him through the end of this Congress, but Hatch late last week made it clear that he wanted to have no part of the arrangement.