Yes, it's possible. Though the people in states that think they're still fighting the civil war will bring it down quite a bit of course, making it unlikely (though possible overall).
Obama already won the "white vote" in many of the Democratic states, and was very close even in some of the swing states.
Looking over the
CNN dataOver 60% of the white vote
DC
Hawaii
Vermont
55-59%
Maine
Massachusetts
Oregon
Rhode Island
Washington
50-54%
California
Colorado
Connecticut
Delaware
Illinois
Iowa
Michigan
Minnesota
New Hampshire
New York
Wisconsin
45-49%
Indiana
Maryland
Montana
New Jersey
Ohio
Pennsylvania
40-45%
Arizona
Florida
Kansas
Missouri
Nebraska
Nevada
New Mexico
North Dakota
South Dakota
West Virginia
Less than 40%
Alabama
Alaska
Arkansas
Georgia
Idaho
Kentucky
Louisiana
Mississippi
Oklahoma
North Carolina
South Carolina
Tennessee
Texas
Utah
Virgina
Wyoming
So, in a "Whites only" election Obama wouldn't have won, but still would have gotten more EVs than McCain actually got. (222 if my count is correct). Not nearly as extreme a situation as our racial revisionists would have you believe.
To contrast, and the data is a little more limited, for McCain's performance among non-white/non-Hispanics, there are no states where he won a majority. Because of this, I have to adjust the scale of the list downward quite a bit.
Over 40%
Alaska (other)
Arizona (Latino)
California (other)
Florida(Latino)
30-39%
California (Asian)
Colorado(Latno)
Hawaii(Asian)
Michigan(Latino)
New Mexico(Latino)
Texas(Latino)
Virginia(Latino)
20-29%
California(Latino)
Indiana(Latino)
New Jersey(Latino)
New Mexico(Other)
Pennsylvania(Latino)
10-19%
Hawaii (other)
Less than 10%
All states(African American)
No need for a map on this one ("No whites" election) as it's so one sided.
Best and worst states for each candidate by race:
McCain:White
Best: Alabama/Mississippi (88%)
Worst: D.C. (12%)
African-American
Best:Wisconsin(9%)
Worst:New York(0%)
Asian (only two states with exit poll data)
Best: California(35%)
Worst:Hawaii(30%)
Latino
Best:Florida/Arizona(42%)
Worst:New Jersey(21%)
Other:
Best:Alaska(46%)
Worst:Hawaii(18%)
Obama:White
Best:D.C.(86%)
Worst:Alabama(10%)
African-American
Best:New York(100%)
Worst:Wisconsin(91%)
Asian (only two states with exit poll data)
Best: Hawaii (68%)
Worst:California(64%)
Latino
Best:New Jersey(78%)
Worst:Arizona(56%)
Other
Best:Hawaii(80%)
Worst:Alaska(52%)