Conservative activists are ramping up pressure on Senate Republicans to install Sen. Jeff Sessions (R-Ala.) as the new ranking member of the Judiciary Committee as the position has taken on added urgency thanks to the likely retirement of Supreme Court Justice David Souter.

Conservatives on and off the Hill have become particularly concerned that Sessions’ ascension on Judiciary will be blocked by Sen. Chuck Grassley (R-Iowa). Grassley, the ranking member of the Finance Committee, is technically in line to take over for Sen. Arlen Specter (Pa.), who switched to the Democratic Party earlier this week.

But Grassley wants to stay on Finance until after his re-election next year. He is pushing a plan under which Sen. Orrin Hatch (R-Utah) would take the ranking member slot on Judiciary in a caretaker capacity until the end of this Congress.

Grassley would then assume the ranking slot on Judiciary, while Hatch would take over as the top Republican on Finance, essentially freezing Sessions out.

Grassley’s plan, on which he is actively lobbying Members, would require approval by the committee’s Republicans, ratification from the full GOP Conference and a special waiver for Hatch because the party’s term-limit rules technically bar him from serving as ranking member.

Conservatives, however, prefer Sessions because of his positions on a host of issues under the Judiciary Committee’s jurisdiction, including Supreme Court nominations and immigration reform.

Although the prospect of Grassley or Hatch taking the Judiciary ranking member slot was sure to cause heartburn among hardline conservatives anyway, Souter’s rumored decision to step down from the high court has pushed the issue to the forefront. The ranking member will be the field marshal for Republican opposition to President Barack Obama’s associate justice nominee.

The conservative blog redstate.com and other activists and media outlets already have started pushing back against Grassley. They are organizing call-ins to Minority Leader Mitch McConnell’s (R-Ky.) office, urging him to block his ascension on the panel. Redstate.com urges readers to register their opposition to the Grassley plan, arguing that “to have Orrin Hatch or Chuck Grassley at the helm would be an unmitigated disaster. Each are cut from the same cloth — that of the old guard Republicans in the Senate who have given us the train wreck that the Party has become.—

A GOP leadership aide, however, said there is little that McConnell can do at this point, and the Minority Leader is almost certain to avoid choosing sides in the brewing dispute. But the source said that if Grassley can persuade enough Members to back him, the Conference rules allow for it.

Grassley could also simply assert his seniority on the Judiciary panel and take the ranking member slot immediately, forgoing the top position on Finance for the remainder of the 111th Congress.