I'm trying to figure out what angle she is working. Either she is incredibly dumb and believes that she can actually win over independent voters with her extreme views or she is intentionally doing this. Her plan may be to stay hardcore on her views and build up a following just as Sarah Palin did. Bachmann may have no plans of actually winning the presidency.
I think her calculus would be to do whatever she can do to win her side of the bracket then walk all over a lamed Obama in the championship game or at minimum have puncher's chance.
Meaning, Bachmann (and many others who think like her) believe firstly...it was an aberration for the O man to have been elected in the first place. That it occurred in two parts; because the media created it and the opposition ignored Obama's un-Americanism, etc. (wrong). Now she believes Obama having failed miserably (in her mind and the minds of those who think like her...and again wrong) and the fact that Americans won't get snowed by Obama's mainstream media this time..
Ergo, all she has to do is somehow get through and win the wacky GOPer primaries where anything (like this pledge) goes and she's a shoe-in to beat 'Obomma'...