Read the article. It is mentioned that the president is going to seek trust vote, as it was on left's support letter the UPA was asked to form the governemnt after the election results were declared. Thier support tilted the balance then and for the future of the government.
Had SP submited a letter of support to the presedent (as it is not mandatory now) and had it tilted the balance, then may be there could be an option as not to seek trust vote.
But in a democratic setup, it is a rule to seek trust vote when there is visible tilt in the balance be within the positive side also.
Note: Kalam asked left a letter of support to ensure the stabilty of government and to sapre the the tax payer from another election is a short time
