Noam cites a National Review article by Ramesh Ponnuru and Rich Lowry to cite his contention that painting Barack Obama as a flip-flopper is a weak tactic. I'll see his Lowry/Ponnuru and raise him a Stephanopoulos:
The ABC poll found that in March, 66% of voters under the age of 30 said they would vote in November no matter what. Today, that number is down to 46% -- a far more typical measurement of the engagement of young people in politics.
ABC's George Stephanopoulos says enthusiasm for the Democratic candidate among young voters "has been dampened" and "all of the questions in recent weeks on whether or not Barack Obama is shifting positions, becoming 'a typical politician,' is turning some of them off."
Note that my clip involves actual data.