This item has been updated.

The surprise announcement that Sen. Max Baucus (D-Mont.) will be nominated by President Obama to serve as the next U.S. ambassador to China not only bolsters the chances of Democrats maintaining control of the Senate, but also will set off a series of changes atop several Senate committees.

Senate Majority Leader Harry M. Reid (D-Nev.) said Thursday that no final decisions have been made on who will climb the ranks of affected committees.

"We're going to wait until this deal with Baucus happens" to make any changes, Reid told reporters. "One of the things we always have a problem here in Washington with is getting ahead of ourselves. I'm not going to do that."

But we will. So follow along as we weave through a potentially complicated maze of Senate seniority.

Baucus, who already announced plans to retire after next year, has been the top Democrat on the powerful Senate Finance Committee since 2001. Sen. Jay Rockefeller (D-W.Va.) is the panel's second-ranking Democrat, but he already chairs the Senate Commerce and Transportation Committee and also is retiring after next year. So the Finance Committee gavel is expected to go instead to Sen. Ron Wyden (D-Ore.), who currently chairs the Senate Energy and Natural Resources Committee, but is eager to lead a more prominent panel, according to several senior Senate aides.

So once Wyden goes, who takes over Energy? Sen. Tim Johnson (D-S.D.) is next in line, but he already chairs the Senate Banking Committee and also plans to retire after next year. So here again, Democrats are likely to turn to the third-ranking member, Sen. Mary Landrieu (D-La.). Landrieu faces a tough reelection battle next year and her leadership of Energy might put her at odds next year with the Obama White House, which is reportedly planning to take a series of executive actions regarding energy policy and climate change.

If Landrieu takes over Energy, she would need to relinquish her leadership of the Senate Small Business Committee. On this panel, Sen. Maria Cantwell (D-Wash.) ranks second, but she already chairs the Senate Indian Affairs Committee.

So if Cantwell opts to lead the Small Business Committee and drop her chairmanship of the Indian Affairs panel, Sen. Jon Tester (D-Mont.) -- Baucus's home state colleague -- would become a committee chairman for the first time.

Again, none of this is set in stone, and up and down the chain a senator might surprise colleagues and decide to make a change, stay put, or decline the gavel. But whatever happens, the impact of Baucus's earlier-than-expected departure would ricochet around the chamber.