2) Democrats would need at least 34 out of 54 Senate Democrats in order to get to a majority — in other words, at least 16 of the 27 undecided Democratic senators. (For the purposes of this exercise, Democratic-caucusing independent Sen. Angus King is a Democrat.)

That may not seem like a tough haul — given that this is Obama’s own party — but look at some of the folks on this list of 27:

* Noted liberals like Sens. Tammy Baldwin (D-Wis.), Elizabeth Warren (D-Mass.), Mazie Hirono (D-Hawaii), Ed Markey (D-Mass.), Jeff Merkley (D-Ore.) and Ron Wyden (D-Ore.).

* Senators facing reelection in 2014 in tough states, including Sens. Mark Begich (D-Alaska), Mary Landrieu (D-La.) and Mark Udall (D-Colo.). And future top GOP targets like Sens. Michael Bennet (D-Colo.), Joe Donnelly (D-Ind.), Jon Tester (D-Mont.) and Claire McCaskill (D-Mo.).

* Retiring Democratic senators in red states: Sens. Jay Rockefeller (D-W.Va.), Tim Johnson (D-S.D.) and Max Baucus (D-Mont.).