One underappreciated aspect of Congressional power is the role of committee chairs in steering legislation. Sen. Patrick Moynihan, as chairman of the Finance Committee, almost single-handedly spiked Hillary Clinton’s health care plan. He simply didn’t like the plan and he won a battle for jurisdiction over the bill with Sen. Kennedy who, then as now, was chairman of the Health Committee.

Committee chairs are generally given out by seniority, although no single senator is allowed to chair more than one committee (it is permissable to be the Ranking Member of more than one committee, however). The illness of Sen. Kennedy and the aging of Sen. Robert Byrd threaten to cause a case of musical chairs in next year’s Congress. To demonstrate this I am going to assume that both Kennedy and Byrd will step down from their chairmanships in the next Congress. This will create openings on the Health, Education, Labor, and Pensions (HELP) and Appropriations committees. And then one of two things will happen and depending on which, we’ll see a much different power structure.

The most coveted chair is the chair of Appropriations because that committee holds the pursestrings of the Senate. If Byrd steps down because he cannot handle the workload, then Sen. Daniel Inouye of Hawaii is next in line. But it’s an open secret in Washington that the second-in-line, Sen. Patrick Leahy of Vermont, has been lobbying to skip over Inouye and grab control of the committee.

In this game of musical chairs, everything depends on whether it is Leahy or Inouye that gets to chair the Appropriations committee. Let’s look at both scenarios. First, let’s assume that Leahy wins out. With Leahy moving to Appropriations, he must relinquish his chairmanship of the Judiciary Committee. The next in line at Judiciary are Sens. Teddy Kennedy and Joe Biden. Kennedy is unlikely to take the chair and Biden would probably prefer to keep his position as chair of the Foreign Relations committee. That means that chair of the Judiciary Committee would fall to Sen. Herb Kohl of Wisconsin. Kohl would then be in charge of pushing through all nominations to the Supreme Court, whether they be appointed by Barack Obama or John McCain. It would then be necessary for Kohl to relinquish his chairmanship of the Committee on Aging. That position would likely be assumed by Sen. Ron Wyden of Oregon, who would attain the rank of chairperson for the first time.

Meanwhile, with Kennedy vacating his chairmanship of the HELP committee, another reshuffling of chairs would occur. Next in line at HELP are Sens. Chris Dodd and Tom Harkin. But they are already chairs of Banking and Agriculture, respectively, and they’d be unlikely to swap those positions out for the chair of HELP. That means the chair could fall to Sen. Barbara Mikulski of Maryland. She would be a first-time chairperson and newly in charge of Labor issues, as well as Education policy.

In this scenario, (assuming an Obama presidency) Inouye would be in charge of ushering through Obama’s Energy plan, Kohl would responsible for his judicial nominees, Mikulski would handle No Child Left Behind reform, and Leahy would control the money. (In both scenarios, Sen. Max Baucus would be in charge of universal health care).

In the second scenario, where Sen. Inouye get the chair of Appropriations, Patrick Leahy stays on as the chair of Judiciary but a vacancy is created at Commerce. Sen. Jello Jay Rockefeller would take over at commerce by abandoning his chair of Intelligence. Sen. Diane Feinstein of California would take over Intelligence by leaving her chair at Rules. The chairmanship of the Rules Committee would most likely fall all the way to Sen. Chuck Schumer, giving him his first chairmanship ten years after his election to the Senate. Herb Kohl would keep his chair at Aging and Mikulski would probably still get her chair at HELP.

I know that’s a mindnumbing amount of chairswapping to keep track of but it can be boiled down to this:

Aging: Ron Wyden or Herb Kohl
Appropriations: Patrick Leahy or Daniel Inouye
Commerce: Daniel Inouye or Jay Rockefeller
HELP: Barbara Mikulski replacing Teddy Kennedy
Intelligence: Jay Rockefeller or Diane Feinstein
Judiciary: Herb Kohl or Patrick Leahy
Rules: Diane Feinstein or Chuck Schumer

The Committee on Aging isn’t very important, but it could make a big difference in what kind of energy policy we get if the bill has to go through Jay Rockefeller who represents Big Coal in West Virginia. Herb Kohl could probably be relied upon to do a good job with Obama’s judicial nominees, but how well would he do vetting McCain’s? Compared to Leahy? And would anyone feel comfortable with Diane Feinstein chairing the Intelligence Committee? I know Rockefeller is bad, but please…

Depending of the breaks, Sens. Wyden, Mikulski, and Schumer could wind up as chairpersons for the first-time. How would Mikulski be on Labor and Education policy? How would Schumer use his chairmanship of the Rules committee?

It’s unlikely that Sen. Inouye will seek reelection in 2010, setting up another major reshuffling of senatorial power in 2011. With the fading away of old lions like Byrd, Kennedy, Inouye, and Ted Stevens, there will be a new culture in the Senate. And that is true even before we take into consideration the huge cultural changes coming on just the Republican side with the retirements of John Warner, Chuck Hagel, Wayne Allard, Larry Craig, and Pete Domenici, and the imminent defeat of two to seven additional Republican senators.

Will Mitch McConnell win relection? Will he hold onto his position as Minority Leader? Could Lamar Alexander take over as Minority Leader and how would that change the feel of the Republican opposition?

Major changes are on the way and a lot depends on little decisions like whether Leahy or Inouye will get the chair of Appropriations.