A pledge with no sincerity adds to the paper junk
However, signing it neither endears me nor does it mean I will have to vote for the party that has forced me to do something against my own free will and independent judgment. On the contrary, I will exact a price for it and will vote against all such wilful parties.
Making us sign the 'pledge' under duress, threat or undue influence is not a very wise move because at the end of the day, is there any moral or religious obligation not to break promises made? No.
St Thomas Aguinas once said that any unjust law and regulation is made to be broken. Since there is no morality in the Aku janji pledge or the heartfelt sincerity and willingness on the part of the signatories, anyone can just sign and then forget about it.
The paper on which the 'pledge' is printed could have been used for something more useful and meaningful.

