With Budget Chairman Jim Nussle (R-Iowa) term-limited out of his post at the conclusion of the 109th Congress, it has long been clear that there would be a race for the gavel in 2007. But in recent months, two key events have lent that contest a new urgency.

In January, Nussle formed a gubernatorial exploratory committee, raising at least the possibility that he will step down from his chairmanship ahead of schedule to focus on a statehouse campaign.

And earlier this month, Budget Vice Chairman Rob Portman (R-Ohio) resigned from the House to take over as U.S. trade representative, leaving the panel’s No. 2 slot — and the chairmanship race — wide open.

Portman had been seen as Nussle’s heir apparent, so the succession picture could become clearer once Portman is replaced as vice chairman, a move that could happen soon.

“No decision has been made yet,” said Hastert spokesman Ron Bonjean. “The Speaker intends to meet with Chairman Nussle later this week to discuss the issue.”

With Portman out of the running, potential candidates to succeed Nussle include a trio of current panel members: Reps. Adam Putnam (Fla.), Paul Ryan (Wis.) and Jim Ryun (Kan.).

While the race remains in its infancy, leadership aides and committee insiders said they see Putnam and Ryan as the most viable entrants.

Though Putnam, 30, is one of the House’s youngest Members and is in only his third term, he has quickly become a favorite of the Republican leaders who will select the next chairman, particularly Speaker Dennis Hastert (Ill.).

Putnam is currently fourth on the Budget panel’s roster, and he also received a vote of confidence from the leadership when he was placed on the Rules Committee.

“I am flattered to be in the mix of those being considered for Budget Committee chairman when Mr. Nussle leaves Congress, but any speculation at this time would be premature,” Putnam said.

At 35, Ryan would also add some youth to the position. He served on the panel in his freshman term and returned to the committee this Congress following a four-year absence.

The conservative Wisconsin lawmaker has been a vocal proponent of budget process reform, and he and a handful of fellow Republican Study Committee members will join today to unveil legislation to overhaul the Congressional spending system.

A member of the Ways and Means Committee, Ryan has also been an active player in the current Social Security debate. Presumably, Ryan could win the Budget chairmanship without giving up his other committee assignment, since Nussle also holds a seat on Ways and Means.

Ryan’s office declined to comment on his level of interest in the Budget race.

While Ryan technically is far down the Budget seniority list, Portman’s departure elevates Ryun to No. 2, and is he openly considering a chairmanship run.

“That is something the Congressman will be interested in,” said Ryun spokesman Nick Reid.

Ryun has led a fairly quiet House career to date but has been active on the Budget panel. The Kansan served as a conferee on the recently adopted fiscal 2006 spending blueprint.