Percent of the independent vote in contests thus far this cycle (where exit polling is available):
Obama Clinton Obama Clinton
AL: 48 48 NJ: 49 43
AZ: 47 37 NM: 65 29
AR: 32 56 NY: 55 40
CA: 58 34 OH: 50 48
CT: 62 32 OK: 38 41
DE: 50 44 PA: 54 46
GA: 63 33 RI: 47 52
IL: 72 22 SC: 42 26
IA: 41 17 TN: 47 43
LA: 53 36 TX: 49 48
MD: 62 27 UT: 68 26
MA: 42 54 VT: 65 35
MS: 53 43 VA: 69 30
MO: 67 30 WI: 64 33
NV: 47 33
NH: 41 31
Clinton won independents in just four states out of 30 states with exit polls. And in the caucus states, she likely lost those as well. Now Clinton supporters will argue that most of these states voted before the Jeremiah Wright video got played 46 billion times on the networks, and that the numbers would look a lot different if those states voted again.
But check out Pennsylvania, which was the first state to vote after Wright. Much has been made about how similar PA and OH are demographically. And they both delivered victories to Clinton by almost identical margins. Yet look at the independent percentages:
Obama did better with independents in Pennsylvania post-Wright than he did in Ohio pre-Wright. Is it an ironclad apples-to-apples comparison? Of course not, but it is suggestive.
Clinton has a problem attracting independent voters, a phenomenon reflected in general election polling. Here are the" independent" crosstabs in several key battleground states:
Obama v McCain Clinton v McCain
CO (Rasm) 44 34 29 48
IA (SUSA) 41 49 32 58
OH (SUSA) 47 45 47 50
MN (SUSA) 42 49 37 53
NV (Rasm) 57 37 36 45
NM (SUSA) 42 46 37 54
PA (Rasm) 39 40 29 48
TX (Rasm) 47 45 35 52
WI (SUSA) 46 45 36 53
(Note that in the Rasmussen polls, the crosstabs are subscription-only.)
In those polls (all of them post-Wright), Obama wins Colorado, Clinton loses it. Obama wins Iowa, Clinton loses it. Obama wins Minnesota by six, Clinton wins it by just one. Obama wins Wisconsin, Clinton is tied. The both lose New Mexico, but only because both candidates haven't locked down Democrats. Clinton wins Ohio (she gets Democrats), Obama loses it (he doesn't -- yet). In Nevada, Obama loses by five, Clinton by 11.
The difference in all of these states between Obama and Clinton, other than the fact that he gets more independents, is that the Democratic base is stronger for Clinton than Obama. That's likely an artifact of the bitter primary, and will fade once we have a nominee. Other than a statistically insignificant number of dead-ender malcontents, those undecided Democrats aren't going to vote for McCain.
Again, more evidence that Obama's upside is much stronger than Clinton's. It'll be far easier for Obama to rally the Democratic base than for Clinton to rally independents. Her task wouldn't be impossible, just not the same as rallying your own party.
There's one exception to this rule I found in my quick perusal of polls -- Florida. Obama loses independents in Rasmussen's latest poll 55-37, Clinton wins it 56-32. It's the difference between Obama losing big, and Clinton holding a one-point lead.