On May 17, 2018, BS Yeddyurappa of the Bharatiya Janata Party (BJP) took oath as the 19th incumbent Chief Minister of Karnataka and was given 15 days for the floor test to prove his majority.
A Chief Minister appointed by the Governor can be asked to prove his majority in case of doubt.
An example of this would be the first state assembly elections after independence in Tamil Nadu. The year was 1952 and it was then known as Madras. The INC got 152 MLAs out of 375, which was close to the required number – that of 188 – to form the government. As it was the single largest party, after 10 days of indecision, the leader of the Vidhayak Dal of Congress C. Rajagopalachari was invited by the then-Governor of the state Krishna Kumarsinhji for forming the government.
But he was given three months for the floor test to prove his majority, and this gave C. Rajagopalachari enough time to engineer the defections among the non-Congress fronts. So, after three months he proved his majority with the support of 200 MLAs and won the trust vote.
Thus, C. Rajagopalachari of the Indian National Congress became the first Chief Minister to survive the trust vote.
We’ll have to wait and see if BS Yeddyurappa can do the same.